Sonic Anniversary Collection

Sonic Anniversary Collection is a compilation of Sonic's classic adventures in one handy package, released for the hedgehog's 30th anniversary, with some fun extras and additional QOL improvements. The collection was released for the Nintendo Switch, PlayStation 4, PlayStation 5, Xbox One, Xbox Series X, and PCs, selling for $29.95 USD.
==Showcased Games==
Sonic Anniversary Collection showcases the following games:
Game	Description
Sonic the Hedgehog
Sega Genesis / Mega Drive
June 23, 1991	Sonic the Hedgehog's first-ever video game adventure! Using Sonic's speed and acrobatic prowess, tear through South Island in order to defeat the ambitions of the evil scientist Dr. Eggman, who is intent on trapping all of Sonic's animal friends inside of robots and using them to locate the Chaos Emeralds, ancient artifacts of unbelievable power! Sonic the Hedgehog's speed and momentum-based platforming were considered groundbreaking back during its debut, and still continues to resonate today as a fun, exhilarating title.
Sonic the Hedgehog 2
Sega Genesis / Mega Drive
November 21, 1992	The follow-up to the original Sonic the Hedgehog does everything a good sequel should do: More zones, more moves, and bigger stakes. This time, Dr. Eggman has his sights set on world domination with the Death Egg, an orbiting space fortress capable of bringing the planet to its knees. Sonic and his new buddy Tails must trash Eggman's operations on Westside Island and find a way to infiltrate the ominous satellite. Sonic the Hedgehog 2 introduced many new innovations to the franchise, including the multiplayer co-op and competition modes, the ever-handy Spin Dash, and the perennial fan-favorite Super Sonic.
Sonic the Hedgehog 3 & Knuckles
Sega Genesis / Mega Drive
February 2, 1994 (Sonic 3)
October 18, 1994 (Sonic & Knuckles)	A story so epic, it had to be split into two parts. The Death Egg has crashed landed on the floating paradise Angel Island, and Dr. Eggman has tricked the island's guardian, Knuckles, into believing that Sonic and Tails have their sights on the all-powerful Master Emerald. Our heroic duo have their work cut out for them as they strive to shut down Eggman once and for all. Meanwhile, Knuckles endeavors to rid his island home of all invaders as he deals with the rogue remnants of Eggman's robotic army. 
Aside from its narrative advancements, Sonic 3 & Knuckles features bigger, better, and more numerous zones, often featuring exclusive areas only certain characters can access with their unique abilities, as well as the dynamic Elemental Shields, which can bestow Sonic and his friends with new moves and unique properties. All of this was possible with the invention of lock-on technology, allowing players back in the 1990's to combine the original Sonic the Hedgehog 3 and Sonic & Knuckles cartridges into one grand adventure.
Sonic the Hedgehog CD
Sega CD
September 23, 1993	Sometimes considered the odd one out of the original classic Sonic titles, Sonic the Hedgehog CD offers a unique take on the usual Sonic formula: By thoroughly exploring each level, Sonic must journey through time to prevent Dr. Eggman from taking over Little Planet in the past and ruling it with an iron fist in the future. Aside from introducing Sonic's longtime admirer Amy Rose and his most persistent robotic doppelganger Metal Sonic, Sonic the Hedgehog CD is known for having two completely different CD-quality soundtracks, both of which are available for the player to enjoy in Sonic Anniversary Collection.
Blue Sphere
Sega Genesis / Mega Drive
October 18, 1994	Liked the Special Stages in Sonic the Hedgehog 3 & Knuckles? Then you'll adore this bonus title, which players could originally access by locking-on a Sonic & Knuckles cartridge with Sonic the Hedgehog. With 128,016,000 procedural-generated levels to select, Blue Sphere will keep you occupied for a long time! See if you can best the most fiendishly-difficult stages of all! Is unlocked by successfully completing a Special Stage in Sonic the Hedgehog 3 & Knuckles.
Dr. Eggman's Revenge!
Original to the Sonic Anniversary Collection	Dr. Eggman has captured Sonic and his friends and is holding them captive in his latest fortress, Metal Island. The doctor hopes to exhaust his adversaries into submission by subjecting them to all of his old machines, one after another. Can Sonic and company hope to survive in this hostile environment with limited resources and overwhelming odds? Dr. Eggman's Revenge! is unlocked by completing Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic the Hedgehog 3 & Knuckles, and Sonic the Hedgehog CD at least once with any endings.
==Changes - Showcased Games==
Below is a list of changes made to the showcased games in the collection.
*In single-player mode, gameplay runs at a consistent 60 FPS, with no slowdown.
*Sonic the Hedgehog, Sonic the Hedgehog 2, and Sonic the Hedgehog CD now have a Sonic the Hedgehog 3 & Knuckles-styled File Select menu, each with eight save slots. Each save slot tracks the player's chosen character, current zone and act, lives and continues gathered, Chaos Emeralds, Super Emeralds, or Time Stones collected, and any additional optional settings that can be set or toggled on a separate menu. When the player returns to a save file, they start at the beginning of the act the player previously ended their last session in. Once a player receives any ending in a save file, they are free to select any accessible zone from which to start from in that save file. The player may also choose a No Save option, allowing them to play through each game without saving. The player can also select connectivity options for online multiplayer through these Save menus.
*The player can choose to play as Sonic, Tails, Knuckles, Amy, or Sonic and Tails in any game.
**Amy has the same acceleration, top speed, and jump height as Tails in all games. She also has two signature moves: The Hammer Rush and Double Jump. 
***The Hammer Rush is activated by holding the Jump button after jumping. Upon reaching the ground, Amy will start swinging her Piko Piko Hammer wildly as she runs along, allowing her to destroy any unguarded enemies, obstacles, and breakable walls in her path. She'll stop swinging her hammer upon slowing down, jumping or being launched into the air, taking damage, or after about five seconds have passed since activating the move.
***The Double Jump is activated by tapping the Jump button again after jumping. Amy will gain additional height on her jump and also extend her Piko Piko Hammer after activating the Double Jump, increasing the attack radius of her Spin Jump.
*If playing as Sonic, the player can choose to use his sprites from Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic the Hedgehog 3 & Knuckles, or Sonic the Hedgehog CD in any of the four games. Tails can also choose between his sprites from Sonic the Hedgehog 2 and Sonic the Hedgehog 3 & Knuckles. The native sprites for each respective game are the ones initially selected. 
**Additionally, Sonic has two sets of unlockable sprites.
***Metal Sonic - Sonic resembles Metal Sonic as it appeared in Sonic the Hedgehog CD. If selected as Sonic's sprites in Sonic the Hedgehog CD, Metal Sonic will change to have a unique gray coloration. The Metal Sonic sprite set is unlocked upon meeting all the target times as Sonic in each game's Time Attack mode.
***Rabbit Sonic - Sonic resembles one of his prototypical designs, a pale-blue rabbit with a red bowtie and white shoes. The Rabbit Sonic sprite set is unlocked upon achieving the Good Ending in all four showcased games as any character.
*If Sonic and Tails are chosen as the playable characters, a second player may control Sonic or Tails either locally or online. The FPS will be locked at 30 FPS instead of the usual 60 if online multiplayer is utilized. In online multiplayer, the player controlling Tails has their own screen and is free to move around the level independent of the player controlling Sonic. Tails can assist Sonic by airlifting him using Tails's flight or by destroying enemies and damaging bosses. However, Tails cannot lose Rings, open Item Boxes, or utilize certain gimmicks. The player controlling Tails can warp to the location of Sonic at any time via a specific button press. Tails is also automatically warped to Sonic's location during boss battles or after certain other events.
**To accommodate online multiplayer, the options for connectivity settings are available at the main menu for Sonic Anniversary Collection, and the File Select, Competition, and pause menus for Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic the Hedgehog 3 & Knuckles, Sonic the Hedgehog CD, and Dr. Eggman's Revenge! A second player is able to join a game either about to be started from the File Select menu by another player or currently in progress by searching for that player in the Connectivity settings of Sonic Anniversary Collection's main menu. Once connectivity is established and a game either begins or resumes, the player hosting the game decides whether they will play as Sonic or Tails. 
*Pausing the game in Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic the Hedgehog 3 & Knuckles, and Sonic the Hedgehog CD brings up the following options:
**Continue - Unpauses the game.
**Restart - Restarts the player at the beginning of the current act. Does not cost any lives. In Sonic the Hedgehog CD, this will also reset the player's time period back to the Present in non-boss acts.
**Save & Exit- Saves the player's current progress and returns to the game's title screen.
**Connectivity - Allows the player to set up an Internet connection for online multiplayer. For the main campaigns of Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic the Hedgehog 3 & Knuckles, and Sonic the Hedgehog CD, this is mostly in service of the multi-screen co-op mode available when Sonic and Tails are selected as characters. If a connection is established in the middle of a game, the player initiating the connection is given the option to play as either Sonic or Tails.
*Falling Item Boxes no longer crush the player. Instead, in all games Item Boxes bounce on top of the player until they move out of the way.
*Activating Super or Hyper forms now necessitates the press of a secondary button while jumping.
*Super Tails is accessible in all games by collecting seven Chaos Emeralds or Time Stones as Tails. Super Tails has enhanced speed and jump height, but no longer has a quartet of Super Flickies orbiting him that attack enemies. However, if the player collects all seven Hyper Emeralds as Tails in Sonic the Hedgehog 3 & Knuckles, Tails can transform into Hyper Tails instead, who does get the Super Flickies, in addition to unlimited fight and swimming.
*Super and Hyper Amy make their debuts in this collection, upon collecting the Chaos / Time Stones and Super Emeralds as Amy, respectively. Similarly to other Super forms, Super Amy is invincible against most enemies and hazards, and has increased acceleration and top speed, and jumps higher. Additionally, Hyper Amy throws copies of her Piko Piko Hammer whenever she activates her Hammer Rush or Double Jump move.
*Each game now has a Time Attack mode, accessible from each game's title screen and unlocked by completing the game once. In this mode, the player may replay certain acts, with the aim of reaching the Goal Plate as quickly as possible. In this mode, there are no bosses or minibosses, and in some instances level designs are slightly altered to remove boss arenas. Each act has a target time under which the player is challenged to complete the level. Beat a target time and you'll earn a Red Star Ring. The player can also save their top three times for each act and character, as well as upload their times to an online leaderboard. Should the player be unsatisfied with their current Time Attack attempt, they can hold down a button for the level to be reset.
*Most acts now have five Red Star Rings hidden somewhere in them. If touched, the player gains 500 points and the Red Star Ring is considered "collected" across all save files. Collect Red Star Rings to unlock content in the Extras Menu of Sonic Anniversary Collection. Transparent copies of already-collected Red Star Rings can be touched again for the 500 point bonus in subsequent playthroughs. To accommodate Red Star Ring collection, a Red Star Ring section is now present under the Ring counter in the HUD. Five red dots correspond to specific Red Star Rings that can be found in that act. When such a Red Star Ring is located, the corresponding red dot will be replaced with a Red Star Ring icon. Some character-specific routes in Sonic the Hedgehog 3 & Knuckles block access to certain Red Star Rings. If a character cannot collect a Red Star Ring in their portion of a certain act, its red dot will be replaced with a red X icon instead. Also, Red Star Rings are always found in the same location during each time period of Sonic the Hedgehog CD.
**The acts without Red Star Rings are:
***Final Zone in Sonic the Hedgehog
***Sky Chase Zone and Death Egg Zone in Sonic the Hedgehog 2
***Hidden Palace Zone and Doomsday Zone in Sonic the Hedgehog 3 & Knuckles
***All third acts of Sonic the Hedgehog CD
*
*Achievements have been added for showcased games, and can be viewed via Sonic Anniversary Collection's Extras menu. The player will be rewarded for unlocking achievements with varying amount of Red Star Rings.
== Options - Showcased Games ==
The following options can be toggled in Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic the Hedgehog 3 & Knuckles, and Sonic the Hedgehog CD. They are accessible from each save file's personal options list.
* Widescreen - The player can play in either standard definition (as the games were originally presented) or widescreen, which allows the player to see more of their surroundings. Is not selected by default. A variety of decorative screen borders are selectable if the player decides to play in standard definition. Also available in Blue Spheres and Dr. Eggman's Revenge!
* CRT Filter - Applies a faux-CRT filter to the screen while the player is in a game. Is not selected by default. Also available in Blue Spheres and Dr. Eggman's Revenge!
* Unlimited Lives - The player has an infinite number of lives, and does not have to worry about getting a Game Over. If selected, any Extra Life Item Boxes are replaced by 10 Ring Item Boxes instead. Is not selected buy default.
* Unlimited Time - The player is not given the traditional 10-minute time limit to complete a stage. Is not selected by default.
* Screen Panning - The screen pans in whatever direction the player is facing if running at full speed or revving up a Spin Dash or Super Peel-Out. Is not selected by default in all games except Sonic the Hedgehog CD.
* Elemental Shields - Replaces all Shield Item Boxes with one of the three Elemental Shields if selected. Exactly what Elemental Shield replaces a certain Shield Item Box is predetermined by the collection's developers. For example, Labyrinth Zone in Sonic the Hedgehog will have almost-exclusively Bubble Shields, while Marble Zone will have mostly Flame Shield to help protect the player from fiery hazards. If this option is not selected, all Elemental Shield Item Boxes will be replaced by regular Shield Item Boxes. This option is not selected by default in all games except Sonic the Hedgehog 3 & Knuckles.
* Special Stage Retries - If the player fails to collect a Chaos Emerald or Time Stone in any Special Stage, they will be given the choice to retry it. The player can attempt each Special Stage two more times. Only the player's last attempt at the special stage will award bonus points, lives, or continues. Is not selected by default.
* Sonic's Moves - The player is given a list of optional moves for Sonic to use. Any combination of them can be activated.
** Super Peel-Out - If the player holds Up and the Jump button, Sonic will rev his legs in place, running off at high speeds when released. Is not selected by default in all games except Sonic the Hedgehog CD.
** Insta-Shield - If Sonic jumps and then taps the Jump button again in midair, he'll generate a protective shield that lasts for about half a second. In experienced hands, this move is invaluable, allowing Sonic to deflect any oncoming projectiles and more importantly, increase the radius of his Spin Jump attack. Is not selected by default in all games except Sonic the Hedgehog 3 & Knuckles.
** Drop Dash - After jumping into the air, the player can hold down the Jump button, allowing Sonic to roll away at high speeds immediately upon reaching the ground. Is not selected by default.
*Secret Options - Due to the menus and options for most games in the Sonic Anniversary Collection being altered, the methods that players used to access secret features may no longer be available. To remedy this, these secrets can be selected and toggled via the Secret Options, which differ for each game and are not unlocked until the player completes the good ending on their respective game file. Unlike other options selected in each save file, Secret Options are disabled by default and reset to disabled each time the player quits the game or returns to the title screen. There are also secret ways to access the Secret Options early in each game, although this early access is removed if the player quits the game or returns to the title screen.
==Sonic the Hedgehog - Changes & Options==
===Changes===
*After about four seconds on the title screen, slowly-flashing text will appear at the bottom prompting the player to "START GAME".
*A new track, based primarily after the unique melody heard during the end credits of Sonic the Hedgehog for the Master System and Game Gear, has been created for the new File Select menu.
*Is heavily inspired by certain changes made in the Christain Whitehead port of Sonic the Hedgehog, released for Android in 2013.
**The additional level design added to the Whitehead port for Tails and Knuckles has been preserved.
**Special Stages rotate smoothly.
*Characters now have invincibility frames after being damaged by spikes.
*Clouds in the upper background of Green Hill Zone now drift in the sky.
*Splats has been added as a Badnik to a few areas of Spring Yard Zone.
*It's now possible to access the Special Stage if the player brings 50 or more Rings to the end of Scrap Brain Zone, Act 1. It's still not possible in either Scrap Brain Zone, Act 2 or Act 3, given the unique ways those acts end.
*Scrap Brain Zone, Act 3 now has a unique tileset, background, and scenery, resembling an industrialized, grimy version of Labyrinth Zone repurposed by Dr. Eggman into a sewer.
*The "GOAL" spheres in the Special Stages have been replaced with a new dark object featuring a pulsating red "X".
===Unique Options===
*7th Emerald - Adds in an additional Special Stage with a seventh Chaos Emerald to collect. If the player collects seven Chaos Emeralds, they can transform their character into their Super form. Is not selected by default. Once the player collects the seventh Chaos Emerald on a save file, it's impossible to disable this option.
*Spin Dash - Is added as an additional toggleable move under the Sonic's Moves option. If selected, Sonic can perform the Spin Dash. Is not selected by default. 
=== Secret Options ===
In Sonic the Hedgehog, Secret Options can be accessed early by pressing the Up, Action 3, Down, Action 3, Left, Action 3, and Right buttons at the title screen. When this is correctly done, you'll hear a Ring sound effect.
* Debug Mode - Allows the player to move around levels freely and place objects, which differ depending on the zone the player is in. When enabled, the player is able to see what buttons perform which actions in Debug Mode on the HUD. Debug Mode cannot be enabled at the same time that Slow & Frame Skip is.
* Slow & Frame Skip - Allows the player to play the game at a vastly slower speed than normal, or even advance the action one frame at a time. When enabled, the player is able to see what buttons perform which actions in Slow & Frame Skip on the HUD. Slow & Frame Skip cannot be enabled at the same time that Debug Mode is.
* Instant Super Powers - Allows the player to collect 50 Rings and activate a Super state, even if they have disabled the "7th Emerald" option or haven't collected seven Chaos Emeralds if selected. If the player does not collect at least six Chaos Emeralds over the course of the game, they still will not receive the best ending possible. Cannot be toggled if the player already has access to Super forms.
==Sonic the Hedgehog 2 - Changes & Options==
===Changes===
*The options at the title screen of the game are now "FILE SELECT" and "COMPETITION". As such, 2 Player Vs mode is now known as Competition Mode.
*The Options Menu has been removed from the title screen.
*A new track, a remixed version of the map theme for Tails Adventure, has been created for the new File Select menu.
*"MILES" has changed to "TAILS" in the lower left corner of the HUD when playing as Tails.
*The additional level design added for Knuckles in Sonic the Hedgehog 2 lock-on game has been preserved.
*Is heavily inspired by certain changes made in the Christain Whitehead port of Sonic the Hedgehog 2, released for Android in 2013.
**Tails can now fly, swim, and airlift Sonic.
**Hidden Palace Zone is an additional one-act zone not present in the original versions of Sonic the Hedgehog 2. It can be accessed via falling down into a pit in Mystic Cave Zone, Act 2. It has the same level design, enemy types, and boss as Hidden Palace Zone in the Whitehead port of Sonic the Hedgehog 2. Upon completing the level and its boss, players are taken to Oil Ocean Zone, Act 1.
***Unlke the 2013 Christain Whitehead port, the original music for Hidden Palace Zone is used, rather than Mystic Cave Zone's 2 Player Versus music.
**Special Stages are now rendered as 3D environments.
**Chemical Plant Zone, Aquatic Ruin Zone, Hill Top Zone, and Oil Ocean Zone have been added as selectable stages in the game's Competition mode.
*Chemical Plant Zone's boss's chemical dumping attack can no longer be negated by ducking. 
*In Competition mode, additional options are available for gameplay and connectivity settings.
*In Competition mode, the screen is no longer split into two halves if the online multiplayer feature is utilized. If local co-op is used instead, then the screen will retain said split.
===Unique Options===
*Easier Death Egg Zone - Adds three Rings to the beginning of Death Egg Zone. Is not selected by default.
=== Secret Options ===
In Sonic the Hedgehog 2, Secret Options can be accessed early by pressing Up once, Right once, Down twice, and Left four times at the title screen. When this is correctly done, you'll hear a Ring sound effect.
* Debug Mode - Allows the player to move around levels freely and place objects, which differ depending on the zone the player is in. When enabled, the player is able to see what buttons perform which actions in Debug Mode on the HUD. Debug Mode cannot be enabled at the same time that Slow & Frame Skip is.
* Slow & Frame Skip - Allows the player to play the game at a vastly slower speed than normal, or even advance the action one frame at a time. When enabled, the player is able to see what buttons perform which actions in Slow & Frame Skip on the HUD. Slow & Frame Skip cannot be enabled at the same time that Debug Mode is.
* Tails to Miles - Restores the original "MILES" label in the lower left corner of the HUD when playing as Tails if selected.
* Free Continues - Instantly adds 14 Continues to the player's save file. Is disabled if the save file already has 14 or more Continues.
* Instant Super Powers - Allows the player to collect 50 Rings and activate a Super state, even if they haven't collected all seven Chaos Emeralds if selected. If the player does not collect them over the course of the game, they will still not receive the best ending possible. Cannot be toggled if the player already has access to Super forms.
=== Multiplayer Options ===
*Simple Race - If enabled, the only criteria for victory in any given act in non-Special Stage zones is who makes it to the Goal Plate first. If disabled, the winner is determined by who performed better in at least three of five criteria (score, time, total Rings collected, Rings brought to the end of the act, and number of Item Boxes destroyed). Is disabled by default.
*Grand Prix - If enabled, the players will compete in three, five, or seven of the available levels. If disabled, players will only compete in one zone or only the Special Stages. Is disabled by default.
*Tails, Knuckles & Amy Abilities - If enabled, Tails, Knuckles and Amy will have their abilities available to use in Multiplayer Races (flight for Tails, gliding and climbing for Knuckles, and the Hammer Dash and Double Jump for Amy). If disabled, they will be mechanically identical to Sonic. Is enabled by default.
*Teleporter Monitors Only - If enabled, all Item Monitors will switch the player to their opponent's position when broken open. Is disabled by default.
==Sonic the Hedgehog 3 & Knuckles - Changes & Options==
===Changes===
*The "1 PLAYER" option at the title screen of the game is now labeled "FILE SELECT".
*The single-player campaign is normally identical to that of Sonic the Hedgehog 3 locked onto Sonic & Knuckles. However, the player can choose to play through Sonic the Hedgehog 3 or Sonic & Knuckles instead by using the No Save option in the File Select menu.
*Tails and Knuckles have new cutscenes showcasing the beginning of their games in Angel Island Zone. 
**Tails lands and then leaps out of the Tornado.
**Knuckles and some of his animal friends are ambushed by a bomb dropped by an Egg Robo, which Knuckles angrily pursues.
**If Amy is selected, she simply appears at the starting point of Angel Island Zone, Act 1.
*In Knuckles's boss fight in Marble Garden Zone, Act 2, the area along the floor and ceiling where the spike chain emerges from now briefly emits debris particles beforehand.
*The cutscene in Carnival Night Zone, Act 2 where Knuckles shuts off power to the level to hinder other characters has been altered to include an energy barrier separating the player from Knuckles. This barrier immediately dissipates when Knuckles turns off the power.
*The water in Carnival Night Zone, Act 2 now has a surface ripple graphic.
*The infamous barrel of Carnival Night, Act 2 now moves of its own accord.
*Knuckles now has a unique boss for Carnival Night Zone, Act 2, the Egg Slider. It's a large cube-shaped mech that slides around the boss arena, hoping to crush Knuckles. Knuckles has to utilize his climbing and gliding abilities to reach and attack the boss when it's temporarily vulnerable after moving.
*A glitch that automatically kills the player when playing as Tails in Icecap Zone, Act 1 has been fixed.
*In Launch Base Zone, Hyper Tails's Flickies no longer target the red level objects that toggle barriers in the zone when destroyed, in order to prevent the player from becoming trapped.
*When Sonic, Tails, or Amy defeats Dr. Robotnik at the end of Launch Base Zone, Act 2, Dr. Robotnik's Eggmobile sputters and vibrates while exploding before impacting the bottom of the Death Egg, which causes the screen to shake before the Death Egg starts exploding and falling apart. The rest of the cutscene plays out as it did in the original release.
*When Knuckles fights Big Arms at the end of Launch Base Zone, Act 2, the sky in the background now darkens.
*A cutscene has been added between the end of Launch Base Zone and the beginning of Mushroom Hill Zone, showing the Death Egg crash back down into Angel Island. This cutscene uses the background animation from the title screen of Sonic 3 & Knuckles.
*Knuckles now fights an Eggrobo (using new sprites) piloting the Egg Hanger during the boss of Flying Battery Zone, Act 2.
*During the Red Eye miniboss battle in Death Egg Zone, Act 1, it's no longer possible to avoid damage from the miniboss's laser attack if ducking on one of its rotating platforms.
*The mines that the Final Weapon in Doomsday Zone may deploy during its second phase have been resprited to be more noticeable.
*At the end of Sonic, Tails, and Amy's campaigns, the word "SONIC" on the Tornado is oriented correctly, instead of reading right-to-left.
*Special Stages are now rendered as 3D environments.
*Amy is added to the "Sonic the Hedgehog 3 & Knuckles" stinger during Good Endings to the game. As such, Sonic, Tails, and Knuckles have also been slightly repositioned to accommodate her.
*In Competition mode, additional options are available for gameplay and connectivity settings.
*In Competition mode, the screen is no longer split into two halves if the online multiplayer feature is utilized. If local co-op is used instead, then the screen will retain said split.
*In Competition mode, Sonic is now unable to use the Insta-Shield.
===Unique Options===
*Music Options - Swaps certain musical tracks with others depending on which option is selected. Only one option can be selected at a time.
**S3&K - All music is identical to that used in Sonic the Hedgehog 3 & Knuckles. Is enabled by default.
**S3 - Certain musical tracks (the Opening, Knuckles, Miniboss, Invincibility, Super Sonic, and Credits themes, and 1-Up jingle) are replaced with those exclusively appearing in Sonic the Hedgehog 3.
**PC - Certain music tracks (the Knuckles, Credits, and Competition Menu themes, and the level music for all acts in Carnival Night, IceCap, and Launch Base Zone) are remixed versions of the tracks exclusively appearing in the PC port of Sonic the Hedgehog 3 as part of the Sonic & Knuckles Collection. In addition, the Super/Hyper Form theme has been replaced with a remix of its early prototype for Sonic the Hedgehog 3, which was accessible as an unused song in the Sonic & Knuckles Collection.
=== Secret Options ===
In Sonic the Hedgehog 3 & Knuckles, Secret Options can be accessed early by pressing the Up, Up, Down, Down, Up, Up, Up, and Up before the title screen completes its opening animation. When this is correctly done, you'll hear a Ring sound effect.
* Debug Mode - Allows the player to move around levels freely and place objects, which differ depending on the zone the player is in. When enabled, the player is able to see what buttons perform which actions in Debug Mode on the HUD. Debug Mode cannot be enabled at the same time that Slow & Frame Skip is.
* Slow & Frame Skip - Allows the player to play the game at a vastly slower speed than normal, or even advance the action one frame at a time. When enabled, the player is able to see what buttons perform which actions in Slow & Frame Skip on the HUD. Slow & Frame Skip cannot be enabled at the same time that Debug Mode is.
* Secret Special Stages - Allows access to an additional three Special Stages. The player can select to play any of them individually or all three in a preset order. After completion or failure of any of these, the player is taken back to their save file options menu.
* Instant Super Powers - Allows the player to collect 50 Rings and activate a Super state, even if they haven't collected all seven Chaos Emeralds if selected. If the player does not collect the Super Emeralds over the course of the game, they will still not receive the best ending possible. Cannot be toggled if the player currently has access to either Super or Hyper forms.
=== Multiplayer Options ===
*Grand Prix - If enabled, the players will compete in all five available races in Competition Mode. If disabled, players will only compete in one race. Is disabled by default.
*Tails, Knuckles & Amy Abilities - If enabled, Tails, Knuckles and Amy will have their abilities available to use in Multiplayer Races (flight for Tails, gliding and climbing for Knuckles, and the Hammer Dash and Double Jump for Amy). If disabled, they will be mechanically identical to Sonic. Is enabled by default.
== Sonic the Hedgehog CD - Changes & Options ==
=== Changes ===
*Is heavily inspired by certain changes made in the Christain Whitehead port of Sonic the Hedgehog, released for Android in 2011.
**The new looping segments of the musical tracks appearing in the game have been preserved. 
**A secret concept image of Desert Dazzle has been preserved.
*The intro and outro animations have been fully restored to their original full resolution and brightness, while the sounds and songs played during them match that of the original Sega CD release of Sonic the Hedgehog CD, including the presence of all sung lyrics.
*The opening animation, title screen, and file select music when starting up the game change depending on which Music Option was selected on the last save file you accessed. 
**If the JPN/PAL option was selected, the tracks will be "Toot Toot Sonic Warrior", "Title (JPN/PAL)", and "D.A. Garden", respectively.
**If the NA option was selected, the tracks will be "Sonic Boom", "Title (NA)", and "Sonic Boom - Instrumental Ver.", respectively.
*All options originally present at the title screen have been removed. Instead, after about four seconds, slowly-flashing text will appear at the bottom prompting the player to "START GAME".
*Level intros and outros now refer to Zones as Acts.
*The time travel animation is slightly shorter. 
*Metal Sonic's sprites have been modified slightly to give him red eyes at all times.
*In Tails and Knuckles's campaigns, Amy is present in Palmtree Panic and will follow the player around, but will not hug them or emit hearts. Additionally, Amy is kidnapped in Collision Chaos, rescued in Stardust Speedway, and arrives to accompany the player off of Little Planet in Metallic Madness. In Amy's campaign, Metal Sonic attempts to abscond with her at the beginning of Collision Chaos, but is fended off with Amy's hammer and subsequently flees.
*The badniks Tamabboh (in Palmtree Panic), Kabasira (in Stardust Speedway), Mechabu (in Metallic Madness), Scarab (in Metallic Madness), and Pohbee (in Metallic Madness) all have new sprites indicating disrepaired states.
*A new antlion badnik, Pincher, has been added to areas of Tidal Tempest. In its standard state, it periodically opens and shuts its jaws. When open, it can open be safely attacked from above. When closed, it can only be attacked from the side. In its disrepaired state, it looks slightly weathered and saddened, and cannot close its jaws.
*In both Stardust Speedway and Metallic Madness, the badnik Dango has been given a new, magenta color on its shell. Disrepaired versions of Dango also now appear in Stardust Speedway.
*Additional hand-drawn cutscenes have been added to the end of Tails, Knuckles, and Amy's campaigns, showing them landing back at Never Lake (with Amy in tow in the case of Tails and Knuckles) and watching Little Planet warp away. The credits afterwards for these three characters has been modified so that the montage of Sonic traversing the zones over the course of the game has been removed.
=== Unique Options ===
*Easy Time Travel - Makes time travel easier to achieve. Time travel can be achieved by passing a Time Warp Sign, revving up a Super Peel Out or a Spin Dash until the player character starts sparkling, and then releasing. Is not selected by default.
*Super Forms - Allows the player to transform into Super Sonic, Super Tails, Super Knuckles, and Super Amy upon collecting all seven Time Stones. Is not selected by default.
*Music Options - Swaps almost the entirety of the soundtrack depending on what option is selected, with the exception of the all level themes heard during the Past time period. "JPN/PAL" is selected by default.
**JPN/PAL - The music heard in the original release of Sonic the Hedgehog CD in Japanese and PAL regions
**NA - The music heard in the original release of Sonic the Hedgehog CD in North American regions
*Original Spin Dash - If selected, the Spin Dash for all characters is controlled, operated, and looks similar to how it did in the original release of Sonic the Hedgehog CD. If not selected, the Spin Dash instead resembles how it functions and looks in Sonic the Hedgehog 2 and Sonic the Hedgehog 3 & Knuckles. Is selected by default.
=== Secret Options ===
In Sonic the Hedgehog CD, Secret Options can be accessed early by pressing the Right, Right, Up, Up, Down, Down, and Action buttons at the title screen. When this is correctly done, you'll hear a Ring sound effect.
* Debug Mode - Allows the player to move around levels freely and place objects, which differ depending on the zone the player is in. When enabled, the player is able to see what buttons perform which actions in Debug Mode on the HUD. Debug Mode cannot be enabled at the same time that Slow & Frame Skip is.
* Slow & Frame Skip - Allows the player to play the game at a vastly slower speed than normal, or even advance the action one frame at a time. When enabled, the player is able to see what buttons perform which actions in Slow & Frame Skip on the HUD. Slow & Frame Skip cannot be enabled at the same time that Debug Mode is.
* Instant Super Powers - Allows the player to collect 50 Rings and activate a Super state, even if they have disabled the "Super Forms" option or haven't collected seven Time Stones if selected. If the player does not collect the Time Stones or destroy all the Robot Generators in each act over the course of the game, they will still not receive the best ending possible. Cannot be toggled if the player enables the "Super Forms" option and currently has access to Super forms.
* Secrets Input - Includes a toggle and inputs for three sets of two digits (## ## ##). If toggled on, going to the US Sonic the Hedgehog CD manual in the Museum section of Sonic Anniversary Collection will reveal codes scrawled in red ink that can be entered into the digits to access even more hidden goodies.
** 40 12 11 - Reveals an image of Tails holding googles and next to a car, along with the text "See You Next Game - Judy Totoya". "Sonic Boom - Instrumental Ver." will play. Press any button to go back to the save file options menu.
** 44 11 09 - Reveals a rather cute image of Sonic with Japanese text reading "You are cool!". The Japanese version of Palmtree Panic Good Future will play. Press any button to go back to the save file options menu.
**42 04 21 - Reveals a rather dark image of Sonic reimagined as a brooding superhero. The American version of Stardust Speedway Bad Future will play. Press any button to go back to the save file options menu.
**42 03 01 - Reveals Sonic and Metal Sonic, collaborating or possibly competing with each other in a rap session, while Eggman mans a turntable nearby. The Japanese version of the Boss theme will play. Press any button to go back to the save file options menu.
**46 12 25 - Reveals a creepy image of multiple strange-faced Sonics leering from the background, while Japanese text reading "Infinite Fun. SEGA Enterprises" appears in the foreground. The American version of the Boss theme will play. Press any button to go back to the save file options menu.
**18 08 92 - Reveals a screenshot of a planned additional stage for 2011 remaster of Sonic the Hedgehog CD, Desert Dazzle, which was ultimately scraped. The initials "CW" can be seen on the bottom right, presumably belonging to Christian Whitehead, an important member of the remaster team. The theme for Wacky Workbench Past will play. Press any button to go back to the save file options menu.
**23 09 93 - Reveals a screen with the best completion times of all the levels in the game by its original developers. The American version of Wacky Workbench Good Future will play. Press the Up and Down buttons to scroll through the records. Press any other button to go back to the save file options menu.
**07 07 07 - Allows access to an additional Special Stage with bizarre aesthetics. Whenever you fail or succeed at the Special Stage, you are taken back to the save file's options menu. 
**26 02 64 - Displays a rotating image of Little Planet, which is situated above a cloudy sky at shifting times of day, with the words "D.A. Garden" present at the bottom. Various sprites can be seen flying or moving along in the foreground. The player has the ability to move, shrink, enlarge, or affect the rotation of Little Planet, even causing it to start spinning in the opposite direction. The player can also cause Little Planet to shift to a bad or good future version of itself. The controls are listed to the upper-left corner of the screen if Little Planet is moved (including how to leave the D.A. Garden), but disappear shortly if the player stops in input. The music that plays during this depends on the Music Option setting the player has on the save file they accessed the D.A. Garden from, and what time period Little Planet is currently in:
***Present: "D.A. Garden" for JPN/PAL, "Sonic Boom - Instrumental Ver." for NA 
***Good Future: "Collision Chaos Good Future" for JPN/PAL, "Quartz Quadrant Good Future" for NA 
***Bad Future: "Collison Chaos Bad Future" for JPN/PAL, "Quartz Quadrant Bad Future" for NA 
==Blue Sphere - Changes & Options==
===Changes===
*Is unlocked in Sonic Anniversary Collection after successfully completing a Special Stage (collecting a Chaos Emerald) in Sonic the Hedgehog 3 & Knuckles.
*A new title screen has been created for the game, depicting Sonic leaping out of a giant ring with the game's title "BLUE SPHERE" depicted on a ribbon beneath the ring. Additionally, animations of stars and multicolored planetoids emerging from the center of the screen has been added to the title screen's background.
*The game now comes with eight save slots, modeled visually after those in Sonic the Hedgehog 3 & Knuckles. These track how many Special Stages the player has completed, how many they have completed in a Perfect state with all optional Rings collected, and the player's longest chain of completed Special Stages without losing or giving up in a single run. 
**Each save slot can also save the player's current progress in a current run of Special Stages, indicate how many Special Stages have been completed so far in the current run, and the highest difficulty of Special Stage that has been completed in the current run (ranging, easiest to hardest, from 0 to 13). 
*Selecting a save slot brings up more options:
**Character - The player can choose to play as Sonic, Tails, Knuckles, or Amy. Sonic is selected by default.
**Stage Select - How the player selects which Special Stage to play. Each individual Special Stage is represented by a unique 12-digit password. Unlike the original release of Blue Sphere, the password is formatted into three sets of four digits (i.e. 0123 4567 8901). The player can toggle each of these digits manually. Mannually-selected Special Stages that the player has already completed have passwords that are colored either green (not completed in a Perfect state) or yellow (completed in a Perfect state). Special Stage IDs that the player hasn't completed are colored white. If the player is in the middle of a current run, they will not be able to manually toggle the password settings, and the existing or generated Special Stage password from selecting the Next Stage or Random Stage options will be colored red, indicating that the player is obliged to attempt the Special Stage corresponding to the password. There are also some other options:
***Next Stage - Changes the password to the numerically-lowest value that represents a Special Stage that the player has not yet completed on their save file, either normally or in a Perfect state. After selecting this option during a current run, both the Next Stage and Random Stage options will be disabled and the player will be prompted to select Continue to resume their current run. Will also be disabled if the player chose to Save & Exit in the middle of a Special Stage. The player will be obligated to attempt the Special Stage they quit from before moving onto a new Special Stage. In the event that the player has completed all possible Special Stages, this option is permanently disabled, instead replaced with a golden crown icon.
***Random Stage - Changes the password to a random combination that represents a Special Stage that the player has not yet completed on their save file, either normally or in a Perfect state. After selecting this option during a current run, both the Random Stage and Next Stage options will be disabled and the player will be prompted to select Continue to resume their current run. Will also be disabled if the player chose to Save & Exit in the middle of a Special Stage. The player will be obligated to attempt the Special Stage they quit from before moving onto a new Special Stage. In the event that the player has completed all possible Special Stage, this option picks a random Special Stage password corresponding to a Special Stage previously completed by the player.
***Continue / New Run - "Continue" the player's current run on Blue Spheres, which maintains the count of Special Stages successfully completed. If the player chose to Save & Exit after completing a Special Stage, this option will not be available until either the "Next Stage" or "Random Stage" options are chosen and a new Special Stage password is generated. If the player chooses the "Quit Run" option, the "Continue" option changes to the "New Run" option, and the player's progress on their old run is deleted. From here, the player can select a Special Stage password either manually or using the "Next Stage" or "Random Stage" options and then use this option to start a new run.
***Single Run - Disabled if the player is currently in the middle of a run. If selected, the player goes through the Special Stage corresponding to the currently-selected password. If the player succeeds, they are taken to the results screen, which becomes more populated depending on the highest difficulty of Special Stage the player completed, before being taken back to their file menu. If the player fails the Special Stage, they are simply taken back to their file menu. Single Runs do not track the number of Special Stages that the player successfully completes in a row.
***Quit Run - Disabled unless the player is currently undergoing a run. If selected, the player's current run ends and all progress on it is deleted from the save file.
*When a Special Stage during a run is completed, the player is given several options:
**Next Stage - The next Special Stage the player attempts has a selection password that matches the closest subsequent value to the Special Stage just completed, and that the player has not yet completed. In the event that the player completes all Special Stages, this option takes the player to the Special Stage with the next immediate numerical password. 
**Random Stage - The next Special Stage the player attempts is one that the player has not yet completed, but is otherwise random. In the event that the player completes all Special Stages, this option takes the player to a random previously-completed Special Stage instead. 
**Save & Exit - Saves the players' progress during their current run of Blue Spheres, maintaining the number of Special Stages they've completed on their current run on their save file. The player is then taken to the Blue Sphere title screen. 
**Quit - Ends the player's current run on their save file and lets them see the results screen, which becomes more populated depending on the highest difficulty of Special Stage the player completed, before returning them to the Blue Sphere title screen. 
*When a Special Stage during a run is failed, the player is given two options:
**Try Again - The player ends their current run, but is given the option to try the Special Stage again, starting a new run. 
**Quit - Ends the player's current run on their save file and lets them see the results screen, which becomes more populated depending on the highest difficulty of Special Stage the player completed, before returning them to the Blue Sphere title screen. 
*The Sonic & Knuckles background has been removed from the results screen, replaced by a stream of stars spawning from the center of the screen and moving towards its borders, without the planetoids present in the title screen's background animation.
*On the results screen, the Cuckies have been replaced by Flickies, and the Sonic & Knuckles logo has been replaced with Amy sitting atop the Master Emerald and waving at the player.
== Dr. Eggman's Revenge! ==
Dr. Eggman's Revenge is a bonus game that serves as the collection's boss rush. It can be unlocked by achieving any ending in Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic the Hedgehog 3 & Knuckles, and Sonic the Hedgehog CD at least once.
=== Story ===
Our heroes are celebrating their victories together on the beach when they see an odd dark-purple Chaos Emerald suddenly materialize. Moving closer to investigate it, the emerald just as quickly vanishes. Before they have a chance to turn around, Dr. Eggman and a cadre of Eggrobos swoop in and shock them all from behind, rendering them paralyzed. As they lose consciousness, Eggman gloats before them before the Eggrobos drag them away to parts unknown.
The player character wakes up with a start on a dark, concrete floor. They stand up after some difficulty, and discover that they are being held captive in a prison cell. Looking out the cell's window, the camera zooms out to reveal a large metallic prison built atop a rocky, mechanized island, which a subtitle informs us is named "METAL ISLAND". It's storming outside, and a massive wave crashes into the island. Power is briefly knocked out, and the energy beam keeping the player inside their cell dissipates. The player takes the opportunity to escape. As power is restored, Eggman watches the player character running through the halls of their fortress. After banging his fist in frustration, he presses a button and hops into a nearby Eggmobile.
==== Normal Ending ====
Occurs if the player makes it through the Boss Rush for a single game, or otherwise fails to meet the criteria for the Good Ending. Eggman's Eggmobile / Mecha Sonic Mk. II careens out of sight, launching themselves into the sky with a twinkle in the distance. The player character/s are then shown freeing the other playable characters before the four walk out of Eggman's fortress on foot. The credits are interspersed with still images of the playable characters constructing and launching a raft out of mechanical debris with which to cross the sea and return home. After the credits conclude, Eggman / Mecha Sonic Mk. II is shown emerging from a pile of junk, clenching their fists and looking furiously at the camera.
==== Good Ending ====
Occurs only if the player makes it through the Grand Tour without using a single continue. After the defeat of the Giant Eggman Robo / Super Mecha Sonic Mk. II, the floor beneath the player under the player collapses, sending them deep into Eggman's base. They land before a large beam of energy surrounding by several layers of weaponry and traps.
A boss battle against the Core Dynamo begins. The player must destroy seven pillars surrounding the Core Dynamo as it launches it various defenses at the player. When a pillar is destroyed, a Chaos Emerald is revealed and the Core Dynamo ups it attacks. As the last pillar is destroyed, a cutscene is played in which the other playable characters arrive to see the Core Dynamo going critical. As the Core Dynamo explodes, the screen fades to white. After the view returns, it's shown that Tails, Knuckles, and Amy were protected by a shield generated by Super Sonic. As everyone celebrates their survival, Eggman is seen through a large hole in the ceiling fleeing in his Final Weapon mech into space. With the approval of the other characters, Super Sonic quickly rises upwards to pursue Eggman.
Super Sonic defeats Eggman's Final Weapon and lands back down on a rocky cliff where Tails, Knuckles, and Amy are present before depowering. The four watch as Eggman's Final Weapon impacts his wrecked fortress on Metal Island, destroying it completely, before Eggman is launched away as a twinkle in the sky. The heroes laugh as the credits begin to roll. As the credits proceed, the four are seen returning to their lives in still images: Sonic is relaxing on the beach, Tails is tinkering in his workshop, Knuckles is protecting the Master Emerald in a new shrine high in the mountains, and Amy is reading about the latest exploits of Sonic in a newspaper in a cafe. Other images over the credits show plant and animal life returning to Metal Island.
After the credits are complete, Eggman is shown rowing an incapacitated Eggmobile across the ocean. He suddenly rises out of the water on the nose of a surfacing ocra whale. Eggman smiles sheepishly towards the orca before the Eggmobile is bounced towards another orca. The two orcas playfully bounce the Eggmobile between each other as Eggman screams in frustration towards the heavens, with the scene irising out on him mid-bounce.
=== Gameplay ===
Like the other showcase games in Sonic Anniversary Collection, the player begins by selecting one of eight save files to record their progress on. The player can also choose a No Save option or access connectivity options from the File Select screen. After selecting a save file or the No Save option, the player is given several choices to choose before beginning the game.
* Character - The player selects the character/s they wish to play as. The choices are Sonic, Tails, Knuckles, Amy, or Sonic & Tails. All characters have their default moves as in Sonic the Hedgehog 3 & Knuckles.
** Knuckles has a slightly different order of bosses he faces if the Sonic 3&K or Grand Tour Boss Rush options are selected.
** A second player either locally or online can control Tails if the player chooses Sonic & Tails as playable characters.
* Boss Selection - The player selects from which game they wish to face bosses from.
** Sonic 1 - The player faces the bosses from Sonic the Hedgehog.
** Sonic 2 - The player faces the bosses from Sonic the Hedgehog 2.
** Sonic 3&K - The player faces the minibosses and bosses from Sonic the Hedgehog 3 & Knuckles, with the exception of Doomday's Zone's Final Weapon, which is exclusive to the Grand Tour.
** Sonic CD - The player faces the bosses from Sonic the Hedgehog CD.
** Grand Tour - The player faces the bosses from Sonic the Hedgehog, Sonic the Hedgehog CD, Sonic the Hedgehog 2, and Sonic the Hedgehog 3 & Knuckles, in that order. Two additional bosses, the new Core Dynamo and the returning Final Weapon from Sonic the Hedgehog 3 & Knuckles, are also available to fight if the player clears all other bosses without using a Continue.
* Difficulty - The player selects how difficult they want their playthrough to be.
** Normal - Bosses are as difficult as when originally faced in their games of origin. For the Sonic the Hedgehog 3 & Knuckles minibosses and bosses, the difficulty defaults to how difficult they were when faced by Sonic, Tails, and Amy, even if Knuckles is selected as the playable character in Dr. Eggman's Revenge! It's impossible for the player to be harmed or killed in the spaces between boss arenas. The player starts with three Lives and three Continues, and can collect Rings between boss battles.
** Hard - Bosses are harder, having more hit points, faster movements, additional attacks, and differing arenas. The spaces between boss arenas now have Badniks, spikes, and other hazards that can harm the player (although insta-kill hazards, like crushers, are absent). Additionally, the player starts with three Lives and one Continue, and can only collect more Rings after defeating certain bosses during the Grand Tour (Egg Crusher from Sonic the Hedgehog, Egg Spinner from Sonic the Hedgehog CD, Death Egg Robot from Sonic the Hedgehog 2, and Egg Rocket (if playing as Sonic, Tails, Amy, or Sonic & Tails) or Big Arms (if playing as Knuckles) from Sonic the Hedgehog 3 Knuckles.
** Very Hard - Available only if the player has previously completed Hard Mode at least once. The bosses have the same enhancements as they do during Hard Difficulty. Each boss must also be defeated within a time limit. Otherwise, an explosion will fill the screen and the player will immediately die. The spaces between boss arenas have the same hazardous Badniks and obstacles as during Hard Mode. Additionally, the player starts with one Life and no Continues, and is only given the opportunity to collect a single Ring at the very beginning of the run.
Once the player selects their options, they begin their game. At the start of the game and between bosses, the player has to navigate a short chunk of level design that may contain Rings and sometimes Springs or other gimmicks before arriving at the next boss arena. These areas also contain Badniks and other hazards that can harm the player on the Hard or Very Hard Difficulty settings. Once the player arrives at a boss arena, they must defeat the boss within before being allowed to move forwards towards the next boss arena. This continues until the player defeats the final boss of the run determined by their Boss Selection choice.
If the player dies while fighting a boss or uses a Continue, they restart immediately after the boss they had most recently defeated. If the player runs out of Continues, they receive a Game Over and must restart at the first boss if they wish to use that Save File again. If the player exits the game, they can select a Save File to start immediately after the last boss they defeated. If the player completes the game, then they can select any boss or miniboss they wish to start from and begin a new game from there, with a single Ring being available to the player on Very Hard mode regardless of which boss they start from.
=== Available Bosses ===
Below at the bosses the player will face in order depending on what Boss Selection option the player chooses. If the Grand Tour option is selected, all the bosses from Sonic the Hedgehog are faced in order, followed by all the bosses in Sonic the Hedgehog CD, Sonic the Hedgehog 2, and then Sonic the Hedgehog 3 & Knuckles. They are followed by the bosses exclusive the Grand Tour mode, but only if the player has not previously used a Continue during their current playthrough.
Sonic 1 	Sonic CD 	Sonic 2 	Sonic 3&K (Sonic, Tails, Amy, or Sonic & Tails)	Sonic 3&K
(Knuckles) 	Grand Tour only
Egg Wrecker 	Egg-HVC-001 	Egg Drillster 	Fire Breath 	Fire Breath 	Core Dynamo
Egg Scorcher	Egg Tilter 	Egg Poison 	Egg Scorcher Mk. III 	Egg Scorcher Mk. III 	Final Weapon
Egg Stinger 	Egg Bubble 	Egg Hammer 	Big Shaker 	Big Shaker 	
Egg Mobile 	Egg Conveyer 	Egg Claw 	Egg Vortex 	Egg Vortex 	
Egg Spiker 	Egg Razer 	Egg Scorcher Mk. II	Tunnelbot 	Tunnelbot 	
Egg Crusher 	Metal Sonic race	Egg Digger 	Egg Drillster Mk. II (Sky) 	Egg Drillster Mk. II (Interior) 	
 	Egg Spinner 	Eggmarine 	Bowling Spin 	Bowling Spin 	
 	 	Egg Bouncer 	Egg Gravitron 	Egg Slider 	
 	 	Laser Prison 	Big Icedus 	Big Icedus 	
 	 	Mecha Sonic 	Egg Froster 	Egg Froster 	
 	 	Death Egg Robot 	Twin Hammer 	Twin Hammer 	
 	 	 	Egg Cannon 	Egg Rocket & Big Arms 	
 	 	 	Egg Rocket 	Hey Ho 	
 	 	 	Hey Ho 	Egg Scrambler 	
 	 	 	Egg Scrambler 	Gapsule 	
 	 	 	Gapsule 	Egg Hanger 	
 	 	 	Egg Hanger 	Guardian 	
 	 	 	Guardian 	Egg Golem 	
 	 	 	Egg Golem 	Heat Arms 	
 	 	 	Heat Arms 	Mecha Sonic Mk. II & Super Mecha Sonic Mk. II	
 	 	 	Egg Inferno 	 	
 	 	 	Mecha Sonic Mk. II 	 	
 	 	 	Red Eye 	 	
 	 	 	Death Ball 	 	
 	 	 	Giant Eggman Robo 	 	
=== Core Dynamo ===
The Core Dynamo is a new boss that appears as the penultimate foe if the Grand Tour Boss Selection option was selected and the player hasn't used any Continues. The player finds themselves on a circular platform with seven pillars surrounding a glass cylinder containing glowing energy. The objective of the player is to attack each cylinder three times (four times on Hard and Very Hard difficulties), destroying it and collecting the Chaos Emerald inside. Each time the player destroys a pillar, the Core Dynamo adds or alters its attacks or modifies the arena. After the player destroys all seven pillars, the Core Dynamo is defeated.
The list of attacks at the Core Dynamo's disposal and properties of its arena change depending on how many pillars are destroyed.
* 0 Pillars - The Core Dynamo slowly fires projectiles from the background at the player. Each time the player is targeted, a reticule around them will appear.
* 1 Pillar - The Core Dynamo fires its projectiles at a faster rate. A spiked orb is deployed. It steadily travels around the floor of the arena.
* 2 Pillars - Periodically, if the player is near an intact pillar, a laser beam will deploy from the ceiling and follow the player around the arena, driving the player away from the pillar. The laser will always dissipate by the time they reach another intact pillar and two lasers cannot be active at the same time.
* 3 Pillars - A second spiked orb is deployed. It has the same behaviors as the first one, but travels in the opposite direction.
* 4 Pillars - The Core Dynamo's projectile attack is occasionally interrupted with multiple large reticules appearing in random places throughout the arena. After a short countdown, these reticules will fill with an explosive blast.
* 5 Pillars - The floor in some places between pillars will give way to bottomless pits below. If the player is currently not being pursued by a laser attack, the space formally occupied by destroyed pillars will periodically emit columns of electricity, forcing the player to a halt until they stop.
* 6 Pillars - The Core Dynamo's projectile attack is occasionally interrupted by circular blasts of energy from the background to the foreground of the arena. These cover a narrow portion of the entire horizontal expanse of the stage each time they are emitted, forcing the player to either jump or remain under them to stay unharmed. The height at which each blast is emitted depends on the player's location. Each time the Core Dynamo uses its circular blast attack, it attacks with three distinct blasts of energy.
=== Hard Mode and Very Hard Mode Differences ===
The following major changes have been made to bosses when the Hard Mode or Very Hard Mode Difficulty settings are selected.
* Sonic the Hedgehog
** Egg Wrecker - The two platforms are replaced with a single platform that moves to the right and left in the middle of the stage. Takes 12 hits.
** Egg Scorcher - Moves faster. Fireballs in the lava pit in the middle jump higher. Takes 12 hits.
** Egg Stinger - Moves faster. One segment is already missing from both the left and right side of the arena. Takes 12 hits.
** Egg Mobile - Traps have been rearranged to be harder. Water moves upwards at a faster pace.
** Egg Spiker - Moves faster. Bombs now explode immediately on impact. Invincibility frames are slightly longer to prevent the player from bouncing continuously on the boss. Takes 12 hits.
** Egg Crusher - Pistons now move at a consistent speed instead of a slow acceleration. Energy balls move faster and home in closer to the player.
* Sonic the Hedgehog CD
** Egg-HVC-001 - The bumpers on the boss have been replaced with spikes that damage the player on contact. A new launcher attachment lobs a trio of projectiles as the boss winds up for its charging attack.
** Egg Tilter - The breakable pods on the stage now take two hits to destroy. The projectiles that the boss lobs at the player are now spiked and damage the player on contact.
** Egg Bubble - The sides of the area are replaced with spike pits. The boss moves faster and fires projectiles more often.
** Egg Conveyer - Spikes now intermittently travel along the conveyor belt.
** Egg Razer - Spikes now randomly fall from the ceiling during the first and second phases of the boss. The final phase now repeats itself once with a harder sequence of spikes to avoid the second time, totaling 4 hits.
** Metal Sonic Race - A more difficult racetrack has been created, with the primary goal of launching the player backwards via Springs if the player isn't careful. Eggman follows behind more closely.
** Egg Spinner - Moves faster. Each panel now takes 2 hits to destroy, resulting in 8 total hits. After the fourth hit, two Hotaru badniks will appear to perform their usual attacks. If both are defeated, the Hotaru will eventually respawn. 
* Sonic the Hedgehog 2
** Egg Drillster - Moves faster. A new launcher attachment lobs a projectile during each pass of the boss through the arena. Takes 12 hits, with it launching its drill only after the 11th hit.
** Egg Poison - Pumps and dumps its load of chemicals more quickly. Takes 12 hits.
** Egg Hammer - Moves faster. Each of its attacks now releases two arrows instead of one. Spikes are now present on top of the totems. Takes 12 hits.
** Egg Claw - Moves faster. Is situated higher in the arena. A pair of spiked orbs now travel at a moderate speed around the edges of the arena. Takes 12 hits.
** Egg Scorcher Mk. II - Moves faster. Fireball projectiles that spread flames over the arena now occur after Eggman both emerges and retreats into the lava. Takes 12 hits.
** Egg Digger - Moves faster. Spike pits line the sides of the arena. Takes 12 hits.
** Eggmarine - Moves faster. The laser attachment now fires a variable 4 - 6 shots per cycle. Takes 12 hits.
** Egg Bouncer - Its released decoys are more menacing-looking and now explode in a shower of projectiles after 3 seconds or immediately if attacked, damaging the player if they do so. Takes 12 hits, spending its last 4 hits in its final laser-shooting phase.
** Laser Prison - The edges of the arena are now spike pits. Takes 12 hits.
** Mecha Sonic - Moves faster. Takes 12 hits.
** Death Egg Robot - Has a new launcher attachment that lobs trios of projectiles as the boss marches forwards. The floor of the boss arena is now composed of eight sections. If the boss lands on one section twice, the section is destroyed, being replaced by a bed of spikes.
* Sonic the Hedgehog 3 & Knuckles
** Fire Breath - Moves faster. Fires a trio of bombs that land in the arena while it is high in the air traveling to the other side of the arena. Takes 8 hits.
** Egg Scorcher Mk. III - Moves faster. Lobs twice as many fireballs per attack than normal. Takes 12 hits.
** Big Shaker - Moves faster, except during its water churning phase. Each time after the boss churns the water in the arena, the water level rises slightly, completely submerging the arena after four cycles. Its invincibility period after each hit is slightly longer. Takes 8 hits.
** Egg Vortex - Moves faster. The water in the arena is much higher, necessitating that the player use the boss's depth charges to launch themselves out of the water intermittently for air if playing as Sonic, Knuckles, or Amy. Takes 12 hits.
** Tunnelbot - Moves faster. Its attack phase while drilling into the earth now has a spiked column emerge from the floor of the boss arena and move across the arena before returning back into the floor. Takes 8 hits.
** Egg Drillster Mk. II (Sonic, Tails, Amy, and Sonic & Tails) - Moves faster. Now launches a projectile attack towards the player during each of their passes through the arena. Takes 12 hits.
** Egg Drillster Mk. II (Knuckles) - Moves faster. Takes 12 hits.
** Bowling Spin - While the boss is electrified, it showers electrified projectiles from the top of the arena that slowly drift downwards.
** Egg Gravitron - Moves faster, except during its electric beam attack. When using said attack, it also lobs electric projectiles towards the player. Takes 12 hits.
** Egg Slider - Moves faster. The middle of the floor of the arena is now a spike pit, with only the edges safe to touch. Takes 12 hits.
** Big Icedus - Moves faster. Now sweeps across the stage wider and lower during its attack phase, necessitating the player jump over it. Takes 8 hits.
** Egg Froster - The platform of the Egg Froster how retracts and extends periodically, making it harder to hit the boss. After landing 8 hits, the boss will now freeze itself into a cube after each hit and attempt to crush the player by bouncing along the floor three times, after which it will unfreeze and resume its normal behavior. Takes 12 hits.
** Twin Hammer - Two Twin Hammers spawn at beginning of the battle.
** Egg Cannon - Each time the platform at the right of the arena is raised, the boss launches a cannonball twice in quick succession. The flat part of the arena is replaced with a bed of spikes. Takes 12 hits.
** Egg Rocket - Moves faster. The sides of the arena are replaced with spike beds. The first two segments take 6 hits each, with the boss taking 13 hits in total.
** Big Arms - Moves faster. The sides of the arena are replaced with spike beds. Takes 12 hits.
** Hey Ho - Moves faster. Hey Ho's first two chops will always bounce along the ground. Its axe will not get stuck during its third chop. Once it expends all choppable segments, more will fall from the sky instead of it moving into a new location. Spike beds are present on the left and right side of the arena. Takes 8 hits. 
** Egg Scrambler - Spike bars appear at a faster rate as the player runs towards the right. Takes 12 hits.
** Gapsule - Moves faster. In lieu of its usual face, a screen with the number "30" will appear. Every time the player hits its capsule release button, the number decreases by one. Occasionally, Gapsule will electrify itself, being temporarily hazardous to touch while continuing its usual attacks. Is defeated once the screen reads "0".
** Egg Hanger - Moves faster. It periodically releases a plume of flame, especially when the player is overhead. When this happens, two fireballs are also emitted, arching upwards to the left and right. Takes 12 hits.
** Guardian - Moves faster. Any time it recovers after being knocked down or jumps, a shower of damaging debris will fall from the ceiling. If the player is between it and the pool of lava on the left side of the arena, the Guardian jumps up and down in place, advancing no closer to the player while continuously causing debris to fall. The player wins by knocking the Guardian into the lava.
** Egg Golem - Moves faster. The amount of space in the arena is reduced and parts of the floor have been replaced with beds of spikes. The boss still takes only 8 hits to defeat, but the Egg Golem's head must be attacked three times to expose Dr. Eggman and score each hit.
** Heat Arms - Moves faster. The floor of the boss arena is composed of four segments. Each time Heat Arms attacks, it soon afterwards drags down any segment it touched, forming a bottomless pit. These segments return as soon as Big Arms reappears. Takes 8 hits. Can still be defeated without destroying its tendrils, which now each take 6 hits to defeat.
** Egg Inferno - The player engages in a harder auto-scrolling section before facing the boss itself. During its second phase, the platforms and bombs move faster along the surface of the lava. Each time it emerges, the Egg Inferno sends globs of harmful lava flying across the arena. Takes 16 hits from its own bombs to defeat.
** Mecha Sonic Mk. II - Moves faster. Takes 12 hits.
** Super Mecha Sonic Mk. II - Moves faster. During its first phase while flying through the air, it irregularly warps to ground level and sweeps across the arena, before warping back into the air. During its second phase, it now fires its Ring projectiles twice in quick succession at differing angles, making them more difficult to dodge. Takes 12 hits, 6 for each of its two phases.
** Red Eye - Moves faster. During its first phase, it now sweeps a laser beam attack across the floor of arena while its orbs are circling in the air. During its second phase, it now steadily fires electrical projectiles towards the player whenever it's not using its laser attack.
** Death Ball - Each time the player reverses gravity, the opening they emerged from will close its door, forcing the player to navigate to the other side of the arena if they wish to invert gravity again. Takes 12 hits.
** Giant Eggman Robo - Moves faster. During its first phase, the arena is divided into multiple segments. Each time the Giant Eggman Robo uses its fingers to try and crush the player, each finger causes any segment it touched to shortly afterwards be dragged down below with the fingers, forming bottomless pits. After this happens, four missiles are launched from the background, each of which quickly reticules and homes in on the player from above. After all four missiles impact, the fingers come back up and return with them any segments previously dragged down, and repeat the process. During the second phase, the flames spewed by the Giant Eggman Robo have a distinct red-blue coloration and continuously home in on the player for a short while until dissipating.
** Core Dynamo - All of the Core Dynamo's attacks and weaponry occur and move at a faster rate. Each pillar takes 4 hits to destroy.
** Final Weapon - Groups of Rings are sparser and generally occur in smaller groups. The missiles fired the first phase are also more numerous and generally more difficult to avoid. In addition to asteroids and missiles, the player must also avoid electrified cyan prisms, which will stop Super Sonic dead in his tracks and sap 5 Rings from him. At the end of the first phase, the Final Weapon fires its turrets more frequently. During the second phase, the Final Weapon travels to the right much more quickly and Super Sonic must actively boost forwards and try to avoid obstacles to score enough hits before his Ring count is depleted.
**
== Time Attack Mode ==
The Time Attack mode in Sonic Anniversary Collection is unlocked by obtaining any ending in either Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic the Hedgehog 3 & Knuckles, or Sonic the Hedgehog CD. Once a game is completed, all acts from that game (barring a few exceptions) become available in Time Attack mode for all characters.
A Time Attack mode is also available for the different sets of bosses from Dr. Eggman's Revenge!, with the Normal and Hard difficulties for each set having their own records. In Normal difficulty time attack runs, the player gets access to three Rings before fighting each boss. In Hard difficulty time attack runs, the player is only given three Rings at the beginning of the run. Also, the player accesses both Core Dynamo and Final Weapon during a time attack run of the Grand Tour boss selection. To unlock Time Attack mode for Dr. Eggman's Revenge!, achieve any ending from the Grand Tour boss selection.
Time Attack mode is selected from Sonic Anniversary Collection's main menu. Then select your game, then character, and finally act or boss selection to get running. Run past the turnstile to officially begin the clock. The clock ends when you hit the Goal Plate at the end of the stage or land the last hit on the final boss of a boss rush. Minibosses or bosses are not present at the end of normal acts in Time Attack mode, even if they would normally appear. If they player is unsatisfied with their performance, they can hold a secondary button to warp back to the beginning of the act or boss rush, and rush past the beginning turnstile to try again.
Each act and boss rush in Time Attack mode has a target time that the player is encouraged to meet. If the player meets the target time of an individual act or non-Grand Tour boss rush for the first time, the player receives one Red Star Ring. If the player meets the target time a Grand Tour boss rush for the first time, they'll receive five Red Star Rings.
A few acts are not available in Time Attack mode. They include:
*Final Zone in Sonic the Hedgehog
*Sky Chase Zone and Death Egg Zone in Sonic the Hedgehog 2
*Hidden Palace Zone and Doomsday Zone in Sonic the Hedgehog 3 & Knuckles
*All third acts of Sonic the Hedgehog CD
== Unlockable Games ==
In addition to the showcased games above, the following games can be unlocked by fulfilling certain criteria. Unlike the showcased games, these are emulated and do not have a variety of changes and options included. For each of these games, the player is allowed to maintain one save state, allowing them to quickly return to where they last left off. The exception is games that include both their Game Gear and Master System versions on the Sonic Anniversary Collection, which can include a separate save state for each version.
Game	Description 	Unlock Requirements
Sonic the Hedgehog
Sega Master System; Sega Game Gear
October 25, 1991 (Master System)
December 28, 1991 (Game Gear)	Developed alongside its better-known 16-bit counterpart, the 8-bit versions of Sonic the Hedgehog are considered by many to be iconic titles in their own right. Focusing on speedy platforming, Sonic must blitz through zones both familiar and new to rid South Island of Dr. Eggman and his polluting factories. By finding the Chaos Emeralds scattered throughout the game's levels, Sonic may be able to set things right! 	Complete Sonic the Hedgehog (Genesis / Master System version) with six or more Chaos Emeralds
Sonic the Hedgehog 2
Sega Master System; Sega Game Gear
October 16, 1992 (Master System)
October 29, 1992 (Game Gear)	In this 8-bit counterpart to Sonic the Hedgehog 2, Sonic's sidekick Tails has been kidnapped by the nefarious Dr. Eggman, who is ordering Sonic to gather for him the Chaos Emeralds in exchange for the fox's safe return. Rushing through an entirely-original set of locales, Sonic must trash Eggman's robotic guardians and rescue Tails before it is too late! This version of Sonic the Hedgehog 2 introduced many new ways of traversing levels, ranging from mine carts, hang gliders, and floating bubbles!	Complete Sonic the Hedgehog 2 (Genesis / Master System version) with all seven Chaos Emeralds
Sonic Chaos (Sonic & Tails)
Sega Master System; Sega Game Gear
October 25, 1993 (Master System)
November 19, 1993 (Game Gear)	The evil scientist Dr. Eggman has destabilized South Island, causing it to slowly sink into the ocean! Sonic and Tails must locate the Chaos Emeralds to save the island from a watery fate! With new power-ups like Sonic's Rocket Shoes and Tails's newfound ability to fly, Sonic Chaos is Sonic's most action-packed portable adventure yet! 	Complete Sonic the Hedgehog CD with all seven Time Stones
Sonic the Hedgehog Triple Trouble (Sonic & Tails 2)
Sega Game Gear
November 11, 1994	An accident has scattered the Chaos Emeralds! Now it's a mad dash as Sonic and Tails, Dr. Eggman, Knuckles the Echidna, and the nefarious mercenary Fang the Hunter scramble to find them! Features crisp graphics, memorable tunes, and expansive levels that rival that of Sonic's 16-bit adventures! 	Complete Sonic the Hedgehog 3 & Knuckles with all seven Choas Emeralds and Super Emeralds
 	 	
=Extras Menu=
Sonic Anniversary Collection includes a variety of extras, some of which are unlocked by default and others that require the player to spend Red Rings to unlock. This menu is divided into different sections.
==Timeline==
A timeline showing various highlights of the Sonic the Hedgehog history, with applicable release dates and a short little blurb and images accompanying each. Is unlocked from the start.
Title 	Dates 	Blurb
Sonic the Hedgehog 	June 23, 1991 (NA, Sega Genesis)
July 26, 1991 (JPN, Sega Genesis)	Sonic is introduced to the world in his first-ever video game, Sonic the Hedgehog. Features unforgettable characters in Sonic the Hedgehog and Dr. Robotnik, as well as innovative fast-paced and momentum-based gameplay. Liberate the animals of South Island and put a stop to Dr. Robotnik's nefarious schemes!
Sonic the Hedgehog (8-bit) 	December 1991 (NA, Sega Game Gear)
December 28, 1991 (JP, Sega Game Gear)	Sonic's first portable adventure. Instead of being a straight port of the Sega Genesis version of Sonic the Hedgehog, this game features some of its own unique levels and mechanics.
Sonic Eraser 	1991 (JPN, Sega Genesis) 	It's Sonic versus Sonic in this rare puzzle game from early in Sonic's history! Line up three identical pieces to unleash Sonic's Spin Attack on the other player, causing them to temporarily lose control.
Sonic the Hedgehog 2 (8-bit) 	November 17, 1992 (NA, Sega Game Gear)
November 21, 1992 (JPN, Sega Game Gear)	Here's some obscure trivia: Sonic 2's 8-bit version managed to release a little bit before its 16-bit counterpart. In this iteration of Sonic 2, Sonic has to travel through exclusive zones to save his kidnapped buddy, Tails.
Sonic the Hedgehog 2 	November 1992 (NA, Sega Genesis)
November 21, 1992 (JPN, Sega Genesis)	Sonic strikes back in this sequel, bigger and faster than ever before! Introduces the Spin Dash, allowing Sonic to gain a quick burst of speed. Sonic and Tails journey across Westside Island in an attempt to stop Dr. Robotnik and his newest invention, the Death Egg.
Sonic the Hedgehog (manga) 	1992 - 1994 (JPN) 	One of the first Sonic comic publications. A young hedgehog named Nicky transforms into the superhero Sonic the Hedgehog to protect his family and friends from Dr. Eggman and other bullies. Marks the first appearance of Amy Rose and Charmy Bee.
Formula 1 sponsorship 	March 14, 1991 - November 7, 1991 	Sonic's goes even faster than before as a decal on a Formula 1 racing car, as a part of a Sega sponsorship deal.
SegaSonic Popcorn Shop 	April 1993 (JPN, Arcade) 	Undoubtedly one of Sonic's most delicious adventures, the player engages in a mini-game involving Sonic, Tails, and Dr. Eggman as they wait for some real-life popcorn to be prepared.
Archie's Sonic the Hedgehog 	May 1993 - December 2016 (US) 	By far the longest-running adaptation of Sonic to date, this monthly comic book showcased the adventures of Sonic and the Freedom Fighters as they worked to liberate the world from the clutches of the evil dictator Dr. Robotnik and oppose a myriad of other foes. Numerous spin-off issues from the main series were also published, highlighting other characters in the comic's continuity.
Fleetway's Sonic the Comic 	May 1993 - January 2002 (UK) 	Another comic adaptation of Sonic's adventures, this series was notable for being faithful to the games while at the same time very much doing its own thing. An unusually snarky Sonic and his friends oppose the evil scientist Dr. Robotnik and his ambitions for the planet Mobius.
SegaSonic the Hedgehog 	June 1993 (JPN, Arcade) 	In this arcade title, Sonic and his friends Mighty the Armadillo and Ray the Flying Squirrel have been captured by Dr. Eggman and imprisoned on his prison island. Using a trackball, the player must guide Sonic, Mighty, and Ray around hazards and to safety before the island self-destructs.
The Adventures of Sonic the Hedgehog	September 6, 1993 - December 3, 1993 (US) 	The first television adaptation of Sonic. In this comedic slap-stick series, Sonic and Tails wander across the planet Mobius as they oppose Dr. Robotnik and his bumbling robotic minions. Has led to some pretty notorious Internet memes in more recent years.
Sonic the Hedgehog (TV show) 	September 18, 1993 - December 3, 1994 (US)	Also known as SatAM by its fans, this TV adaption of Sonic aired concurrently with its less-serious counterpart The Adventures of Sonic the Hedgehog. In a world were Dr. Robotnik has already conquered most of the planet and turned its inhabitants into robotic slaves, Sonic and a small band of Freedom Fighters work to sabotage the doctor's operations and overthrow his tyrannical rule. Is notable for having influenced the tone of Archie's Sonic the Hedgehog comic book series.
Sonic the Hedgehog CD 	September 23, 1993 (JPN)
November 19, 1993 (NA)	In Sonic's first disc-based game, Sonic travels to the mythical Little Planet and across time to stop Dr. Robotnik from conquering the past, present, and future. Is notable for introducing Metal Sonic to the franchise, Sonic's robotic and deadly doppelganger, as well as having two completely different soundtracks released for the Japanese / PAL region and North American versions of the game.
 	 	
Category:Compilations
Category:Sonic (series)
Category:Sonic Games
Category:2D Platforming Games
Category:SEGA Games