Sonic the Hedgehog 2
Despite "Sonic the Hedgehog" success, Sega was slow to approve the development of a sequel before directing STI founder Mark Cerny to start "Sonic 2" in November 1991. Members of the original development team—including programmer Yuji Naka and designer Hirokazu Yasuhara—moved to California to join the project. "Sonic 2" was intended to be faster and more ambitious than the first game. The development suffered setbacks, including language and cultural differences between the Japanese and American staff, and numerous levels were cut due to time constraints and quality concerns. As with the first game, Dreams  Come True member Masato Nakamura composed the soundtrack. "Sonic 2" was widely anticipated, and Sega backed it with a marketing campaign. It was released in November 1992 to acclaim and received numerous year-end accolades. Critics considered "Sonic 2" an improvement over the first game and praised the visuals, level design, gameplay, and music. The implementation of Tails and the multiplayer mode received criticism, while the special stages divided opinion. "Sonic 2" broke sales records and became the fastest-selling and highest-grossing home entertainment product of 1992, grossing over that year. With 7.55 million copies sold worldwide, it is  the second-bestselling Genesis game behind the original "Sonic the Hedgehog". "Sonic 2" played a major role in keeping Sega competitive during the console wars of the fourth generation of video game consoles in the early 1990s. It continues to receive acclaim, often cited as one of the greatest video games of all time and one of the best "Sonic" games. "Sonic the Hedgehog 3" and "Sonic & Knuckles" followed in 1994. "Sonic 2" has been rereleased on various platforms via compilations and emulation, and a remake for iOS and Android devices, developed using the Retro Engine, was released in December  2013. A number of "Sonic 2" prototypes have leaked since the game's release; the first, discovered in 1999, played a significant role in the development of the archaeogaming scene. Gameplay. "Sonic the Hedgehog 2" is a side-scrolling platform game. It features a story similar to the first "Sonic the Hedgehog" (1991): Doctor Robotnik, a mad scientist, seeks the Chaos Emeralds to power his space station, the Death Egg, and traps the animal inhabitants of West Island in aggressive robots. As Sonic the Hedgehog, the player embarks on a journey to collect the Chaos Emeralds and stop Robotnik. The  player character can run, jump, crouch, and attack by curling into a ball. "Sonic 2" introduces the spin dash, which allows the player to curl while stationary for a speed boost, and Miles "Tails" Prower, a fox with two tails who acts as Sonic's sidekick. By default, the single-player controls both Sonic and Tails simultaneously; a second player can join in at any time and control Tails separately. The player can also choose to play as Sonic or Tails individually. The game takes place across 10 zones with 23 levels (also known as "acts"). The acts are larger  than the first game's, and the player navigates them at high speeds while jumping between platforms, defeating robot enemies, and avoiding obstacles. Springs, slopes, bottomless pits, and vertical loops populate acts, as do hazards like water and spikes. The player passes checkpoints to save progress. The last act of each zone ends with a boss battle against Robotnik. The player collects rings as a form of health: if the player has at least one ring when they collide with an enemy or obstacle, they will survive, but their rings will scatter and blink before disappearing. The player starts with  three lives, which they lose if they are hit without a ring, fall down a pit, get crushed, or drown; they receive a game over if they run out. Power-ups like shields and invincibility provide additional layers of protection, and lives are replenished by collecting 100 rings or a 1-up. If the player passes a checkpoint with 50 or more rings, they can warp to a special stage for an opportunity to collect one of the seven Chaos Emeralds. The player runs through a half-pipe course, collecting rings and dodging bombs. A set amount of rings must  be collected to obtain the emerald. If the player collides with a bomb, they lose ten rings and are immobilized momentarily. The stages rise in difficulty and the player cannot enter any stage without passing the previous one. After finishing, the player is transported back to the star post they used to enter, with their ring count reset. When all the Chaos Emeralds have been collected, Sonic can transform into Super Sonic by collecting 50 rings. Super Sonic is nearly invincible, runs faster, and jumps farther, but loses one ring per second and reverts to normal when his rings  are depleted. "Sonic 2" introduces a multiplayer game mode where two players compete against each other in a split-screen race across three levels. After one player finishes a level, the other player must finish within a minute. Players are ranked in five areas (score, time, rings held at the end of the level, total rings collected, and the number of item boxes broken). The player who excels in the most categories wins. Players can also compete to obtain the most rings in the special stages. Section::::"Knuckles in Sonic 2". "Sonic & Knuckles" was released in 1994, two years after "Sonic  2". The "Sonic & Knuckles" game cartridge features a "lock-on" adapter that allows players to insert other Sega Genesis cartridges. Attaching "Sonic 2" unlocks "Knuckles the Echidna in Sonic the Hedgehog 2", a variation of "Sonic 2" in which the player controls the "Sonic the Hedgehog 3" (1994) character Knuckles the Echidna. The level design is identical, but Knuckles can glide and climb walls, allowing him access to areas inaccessible to Sonic or Tails. However, he cannot jump as high, making some areas, such as certain boss fights, more difficult. Development. Conception. The original "Sonic the Hedgehog" was developed  by Sonic Team in Japan and published by Sega for the Sega Genesis in June 1991. The game greatly increased the popularity of the Sega Genesis in North America and is credited with helping Sega gain 65% of the market share against then-industry leader Nintendo, making Sega a formidable competitor. The success meant that a sequel was inevitable, but shortly after the release, programmer Yuji Naka quit Sega due to disagreements over his salary, dissatisfaction over the time and effort it had taken to finish "Sonic", and a lack of support from management. During the development of "Sonic the  Hedgehog", Mark Cerny established Sega Technical Institute (STI) in California. Sega wanted to develop more games in America, and Cerny's aim was to establish an elite studio that would combine the design philosophies of American and Japanese developers. During a trip to Japan, Cerny visited Naka's apartment, listened to the reasons why he left, and convinced him to join STI in America to fix the problems he had had with Sega in Japan. Designer Hirokazu Yasuhara and other members of the "Sonic" development team joined Naka, but artist Naoto Ohshima stayed in Japan because he was working on  Sonic CD (1993). In September 1991, Cerny pitched "Sonic the Hedgehog 2" as STI's project for the 1992 Christmas and holiday shopping season—giving the team 11 months of development—but Sega management considered it too soon for a sequel. Cerny said that this was not uncommon, as marketing executives controlled what games developers created and did not understand game development. STI explored other concepts, but in November, Sega reversed course and told Cerny that it needed "Sonic 2" for the 1992 holiday season. Cerny said that this did not create "much of a creative loss", as STI had  yet to come up with a game idea on par with "Sonic", but lost two months of development. Now with a nine-month schedule, full-scale development started in early 1992. "Sonic 2" development team was much larger than the first game's and consisted of both American and Japanese developers, although the majority of the team was Japanese. Cerny's idea was to have around a dozen of the original game's staff move to STI. Development began with only Americans because the Japanese faced visa problems. According to Cerny, Sega had applied for O-1 expert visas, for "nationally  or internationally recognized" people with "a record of extraordinary achievement", unaware that the Japanese developers did not qualify. Sega's Masaharu Yoshii was credited as director, though he did not join until halfway through development. Yoshii said that he became involved after Cerny quit and he was installed as the temporary head of STI. However, Cerny said that he left just as development concluded. Over 100 people worked on "Sonic 2" and the main team comprised 20 developers. Design. Sega of America marketing director Al Nilsen said that STI wanted "to go all out" to ensure "Sonic 2" would be  as successful as the original "Sonic", since sequels were generally not well regarded. STI brainstormed various ideas to improve the first game's formula, beginning with making Sonic faster. In the first game, Sonic was restricted by a speed cap well below his maximum possible speed; STI lifted the cap for "Sonic 2". Naka conceived the spin dash to remove the need to backtrack for momentum, which he observed was a common criticism of the first game. Early in development, STI implemented a routine whereby Sonic was hurt if he ran into a wall at full speed, but removed it  in later builds. STI's first step was to create an outline of the game, which the developers then fleshed out with "a book-length report" detailing the characters, story, and levels. Yasuhara had ambitious plans "Sonic 2" and designed it with "'blue sky' ideas". Assuming STI had two years of development, he conceived a plot in which Robotnik took over the world and Sonic used time travel to stop him. "Sonic CD" time travel feature was coincidental, and differed from "Sonic 2" as it implemented it as a game mechanic rather than merely a story feature. The plot was  scrapped, but many of "Sonic 2" levels were taken from it; for example, Hill Top Zone (which features dinosaur enemies) was intended to be a past version of Green Hill Zone, while Chemical Plant and Casino Night came from the Robotnik-ruled future. Yasuhara was inspired to design Casino Night because he noticed that "Sonic" springs felt similar to the gimmicks of pinball tables, while Sky Chase—which features Sonic riding a biplane as he attempts to reach Robotnik's base—was inspired by Hayao Miyazaki's anime "Future Boy Conan" (1978). "Sonic 2" features twice as many unique level  tropes compared to the first game, and STI chose to have most levels end after two acts rather than three. The first game demo was playable around six or seven months after the initial level outline's creation and featured a few levels without sound effects or significant detail. STI assembled focus groups to play the demo for feedback and created the alpha build afterward; by this point, 80% of programming had been finished. Yasuhara wanted to add a second playable character so siblings could play together. An internal contest was held to determine the new character; the winning design  was lead artist Yasushi Yamaguchi's twin-tailed fox, inspired by Japanese folklore about the kitsune. Sega of America objected to the character's name, Miles Prower (a pun on "miles per hour"), so he was given the nickname Tails as a compromise. Tails was implemented using an artificial intelligence routine that allowed him to mimic Sonic's movements, becoming playable with a second controller. Tails was also used in the multiplayer mode, something that Naka had attempted to implement late in development of the original "Sonic". The multiplayer mode was one of Naka's primary motivations to develop "Sonic  2", since he felt multiplayer games were more fun. Naka used the Genesis' rarely-used interlaced mode to create split-screen gameplay; he found the standard display mode made it difficult to see the player character. Developing the multiplayer mode took six months. Art direction. In addition to overseeing the level design and gameplay, Cerny acted as an art director. The initial level maps were drawn at Sega's headquarters in Tokyo. STI artists then received the paper map with ideas regarding the level theme. Once the design was settled, the artist would draw the art pixel by pixel and  then input the graphics in the game itself. The graphics and animations were implemented using the Digitizer, Sega's proprietary graphics system for the Genesis. The artists had to deal with palette limitations, as only 64 colors could be displayed on-screen. Rieko Kodama, who worked on the first game as an artist, helped design the levels. Yasuhara said meshing the Americans' art with art by Yamaguchi was the development's largest hurdle. Yamaguchi had to check the teams' enemy and stage designs while producing his own. While Yamaguchi was assisted by Jina Ishiwatari, he worked mostly alone. Level artist  Craig Stitt called Yamaguchi "a machine" who worked long hours and reworked other artists' levels repeatedly to ensure quality. For example, Stitt felt disappointed when Yamaguchi redid his background art for the Oil Ocean level, but did not argue because he was not satisfied with the original background and Yamaguchi's was much better. Naka and Yasuhara also occasionally checked the art, with artist Tim Skelly noting Naka was quite particular. The title screen and Casino Night level art were both completely reworked shortly before release. Skelly designed the appearance of the pseudo-3D special stages, based on a tech demo  created by Naka. The special stages were created from pre-rendered 3D polygons, video of which was compressed and halved vertically and horizontally to fit in the game cartridge. According to Cerny, the 3D look came from the sentiment that the stages needed to look "flashy". Skelly said that the idea came from STI programmer Steve Woita, who "recalled an interesting scheme that allowed us to do bit-map graphics with a character-stamp based system". Graphics for rings, bombs, and characters were provided by Yamaguchi, while the stages were designed by "Shinobi" (1987) director Yutaka Sugano. In retrospect, Cerny  felt the stages, while visually impressive, did not have as much gameplay depth as the special stages of the original "Sonic", which featured Sonic navigating a rotating maze. Difficulties and cut content. The development was complicated by the cultural and language barriers between the Japanese and American developers. The Japanese were used to crunch conditions, with Cerny noting they often worked through the night and slept in their cubicles. In contrast, the Americans locked the STI offices at night. Cerny had envisioned the Japanese acting as mentors to the Americans, but cooperation was difficult since the Americans could not speak  Japanese. Stitt recalled Yasuhara as easy to work with, but Naka as "an arrogant pain in the ass" not interested in working with Americans. Skelly said that Naka would have been happier working with an all-Japanese team. A large amount of content was cut. Nilsen said "Sonic 2" "probably could have been three times the size if we left in everything that was there. Naka and team really did a phenomenal job of editing what was going to be in the game, and weren't afraid to say, 'I've been working on this for four months, it's  not working. Let's take it out.'" One scrapped stage, Hidden Palace Zone, featured extensively in prerelease advertisements. It was planned as a secret stage accessed by collecting Chaos Emeralds; according to Naka, it would explain the origin of the Chaos Emeralds and grant Sonic his Super Sonic powers. Though Hidden Palace was one of the first levels implemented, work on it stopped in mid-1992, and it was removed shortly before completion for a lack of time and cartridge space. Stitt, who created the Hidden Palace art and considered its foreground among his favorite work, was angry when he learned  it was cut. Other cut levels included a forest level, which was implemented but hardly worked on, and a desert level. One scrapped level, Genocide City, was renamed Cyber City because the Japanese developers had not understood the negative connotations of the word "genocide". Its level layout was used in the Metropolis Zone level. Sega of America CEO Tom Kalinske, product manager Madeline Schroeder, and Nilsen worked closely with STI; Nilsen said the feedback loop helped the team determine what needed to be cut. Most cuts were made to the Americans' designs, and many Americans were furious when they learned  their work had been cut. Stitt said that he may have been the only American whose art was used in the final game. According to Yasuhara, most level cuts were due to time constraints and he had been upset by each of them. In 2017, he said he wanted to remake "Sonic 2" with the cut content restored. "Sonic 2" did not become playable from start to finish until the last 48 hours of development, in September 1992. The team planned to use a 4MB cartridge, the same cartridge size as the first game, but STI ran out of  space towards the end of development. To make sure the game would be finished in time for Thanksgiving, Yoshii went to the Japanese side of Sega for help. Managing director Daizaburou Sakurai contacted Sega Enterprises president Hayao Nakayama, who allowed the team to double the ROM size to avoid a delay. Yoshii said that "Sonic 2" would not have been ready for release without Sega of America's bug-checking process. STI videotaped testers' gameplay so the developers could easily locate bugs. Around 50 developers worked as bug checkers, and the process took two to three weeks. When "Sonic 2  was shipped to Japan for production, copies of the source code were sent on separate planes to ensure that the game would arrive in case of an accident. Music. As with the first game, the Sonic 2" soundtrack was composed by Masato Nakamura, a member of the J-pop band Dreams Come True. Nakamura had become famous in Japan after the release of "Sonic the Hedgehog" and increased his asking price considerably. According to Yamaguchi, a Sega of America employee asked STI to use music composed in-house instead; the team felt the music was "awful" and refused to use  it, so Sega rehired Nakamura. As with the first game, Nakamura began composing early in development with only concept art for reference. He treated "Sonic 2" like a film and attempted to reflect the atmosphere he felt in the concept art. Nakamura composed "Sonic 2" simultaneously with the Dreams Come True album "The Swinging Star" (1992); as a gift to the developers, he produced an alternate version of the "Sonic 2" ending theme, "Sweet Sweet Sweet", for the album. Since "Sonic 2" was more technically advanced than its predecessor, Nakamura "wanted to create music that showed progress... It was like  the "Indiana Jones" sequels. Same concept, but with more fun and excitement." Nakamura felt considerable pressure, as he understood that expectations were high due to the first game's success. STI let Nakamura "do as [he] pleased", which he felt allowed him to create "such melodic tunes and unusual rhythm patterns". He composed using a Roland MC-4 Microcomposer; he noted that it was challenging due to the Genesis' limited sound capabilities, but the limitations encouraged him to be more inventive. Five or six individuals worked to convert Nakamura's music to the Genesis hardware for use in the game. Release . Sega aggressively promoted "Sonic the Hedgehog 2", spending approximately $10 million on advertising. Promotion began in early 1992, when Sega sent mockup screenshots to magazines. Sega then sent an early build to Nickelodeon for demonstration on the "Nick Arcade" (1992) game show; the build was featured several times, notably in a competition between "Clarissa Explains It All" (1991–1994) stars Melissa Joan Hart and Jason Zimbler. Hart "memorably" struggled to play it since she was unaware of the spin dash. As "Sonic 2" was Sega's biggest game of the year, the marketing team, as "Game Informer" wrote, sought to  make the release "as much a celebration as it was a product launch". Sega gave away T-shirts as preorder gifts and sent stores dry-erase boards to count down the days to release. Teaser posters bore the slogan "Are You Up 2 It?". Sega of America collaborated with Emery Worldwide to produce stickers celebrating "The Great "Sonic 2" Shipment", and 50 people dressed as Sonic greeted the three planes carrying copies of "Sonic 2" at Heathrow Airport. Sega considered shipping the cartridges with holographic labels, but decided it was too expensive. At the last minute, Sega canceled a tour  of shopping malls across the US, deciding it would be inadequate. Instead, it made "Sonic 2" available in the West in all stores on the same day. This was an unusual practice at the time; generally, international game release dates depended on the region. Sega reconfigured its distribution system to ensure that games were available in all major stores. The North American and European release date, Tuesday, November 24, 1992, was marketed as "Sonic 2sday". In Japan, the game was released three days earlier, on November 21. Initial copies of "Sonic 2" had several bugs; later copies used a patch  developed a few days after completing the game. The cover art, featuring Robotnik "leering over a checkered '2'" behind Sonic and Tails, was illustrated by Greg Martin. An alternate version of "Sonic the Hedgehog 2" was developed by Aspect Co. for Sega's 8-bit consoles, the Master System and the handheld Game Gear. The 8-bit version of "Sonic 2" features different level designs and music, as well as a different plot in which Sonic must rescue a kidnapped Tails. It was later included in "Sonic" compilations, such as "Sonic Adventure DX" (2003) for the GameCube and Windows and  Sonic Gems Collection (2005) for the GameCube and PlayStation 2. Another version planned for the Genesis's Sega CD accessory became a new game, "Sonic CD". Commercial performance. Following the success of the original, "Sonic the Hedgehog 2" was widely anticipated. Prior to release, the game had already sold units to retailers by October 1992. It set a pre-order record in Europe with game cartridges ordered in five countries, including 750,000 units in the United Kingdom and another 750,000 orders in France, Germany, Spain and Austria. Upon release, "Sonic the Hedgehog 2" broke video game sales records. In the  United States, the game sold copies and grossed within a day. In the United Kingdom, it became the fastest-selling game in history with a record 750,000 copies sold out within a day, grossing or and accounting for 48% of all UK software sales that week. The game's release-day revenue exceeded what 1992's best-selling rock music CD, Simply Red's "Stars", had earned throughout the year. "Sonic 2" was the UK's number-one game during November and December 1992 (above "Street Fighter II" for the Super NES and "Super Mario Land 2" for the Game  Boy during Christmas), and had sold over copies in the UK by the end of the year. For two months, "Sonic 2" was the top-seller on Gallup's Sega charts for the United Kingdom, Japan, and United States. It was the best-selling home video game of 1992 in North America and Europe. It was also the top Genesis video game rental in the United States for three months, from December 1992 to February 1993. It continued appearing on the UK sales charts, returning to the top three in 1993. It became the UK's second best-selling video  game of 1993 with more than 400,000 sales, adding up to more than copies sold in the UK by 1993. The game's initial worldwide batch of cartridges sold out within two weeks, outpacing the original "Sonic the Hedgehog". "Sonic 2" went on to sell copies in a month and units within , and grossed in 1992 ( adjusted for inflation), more than any film or other home entertainment product that year. In November 1993, it was reported to be the best-selling 16-bit video game ever at the time. It continued to appear in the top five on the UK  sales charts two years after its release in 1994. The game had sold copies in North America alone by 1996, more than units in the United Kingdom , 750,000 units in France, Germany, Spain and Austria , and 400,000 units in Japan , for a worldwide total of approximately more than cartridges sold . Reception. "Sonic 2" received critical acclaim, with scores above 90% from most video game magazines at the time. The improvements to the gameplay were praised. "GamePro" commented that "Sonic 2's game play mechanics are the same as Sonic 1's with a few cool exceptions." They gave it a  4.5 out of 5 for sound and a perfect 5.0 in every other category (graphics, control, and fun factor). Critics praised the level design and graphics. "GamePro" assessed that the "graphics are actually better than the original's. The rich variety of scenery, slightly larger sprites, and extra-added attitude help the spunky hedgehog paint video game magic." Despite the reduction in the number of acts per level to two from the first game's three, the levels themselves were said to be larger and more memorable. "GamePro" described Tails as "about the cutest companion that any Sonic fan could  ask for" and said the game's biggest problem is that it is too easy, to the point where even unskilled players would quickly breeze through it. However, the reviewer noted that finding each stage's secrets provides the game with challenge and longevity. Reviewers spoke positively of the special stages and approved of the visual effects. "GamePro" elaborated, "Theoretically, the Genesis isn't capable of scaling, but "Sonic"'s Bonus Rounds are gonna make you wonder!" Accolades. "Electronic Gaming Monthly" awarded it for being the best Genesis game of 1992. The Electronic Gaming Awards from "Electronic Games" magazine  nominated "Sonic 2" for its 1992 Video Game of the Year award, which it lost to "Street Fighter II", but "Sonic 2" won the award for Best Electronic Game Graphics. "Chicago Tribune" selected it as runner-up for Best Game of the Year, below "Street Fighter II" and "". At the Golden Joystick Awards, "Sonic 2" won the awards for Best Original Console Game and Promotional Campaign of the Year. The "Mega" Reader Awards voted it the best platform game and best overall Mega Drive game of 1992, and "Mega" ranked it the second best Mega Drive game of all time  in 1993, before later placing the game at #36 on their "Top Sega Mega Drive Games of All Time" list in 1994. At the European Computer Trade Show (ECTS) awards, it won the Going Live Readers Award. Post-release. Aftermath. Naka refused to develop another "Sonic" game if he had to work with the Americans again. When Atari veteran Roger Hector became the division's head, STI split into two teams: the Japanese developers led by Naka, and the American developers. The Japanese team started working on a sequel—later split into two games, "Sonic the Hedgehog 3" and "Sonic  & Knuckles"—in January 1993; it was conceived as an isometric game that used the Sega Virtua Processor chip, but was retooled to reuse the "Sonic 2" engine after it became apparent that the chip would not be finished in time. Many of "Sonic 2" unused concepts were incorporated in "Sonic 3" and "Sonic & Knuckles", including the Hidden Palace level. Like their predecessors, "Sonic 3" and "Sonic & Knuckles" were critical and commercial successes when they were released in 1994. While the Japanese worked on "Sonic 3", the American team developed the spin-off "Sonic Spinball" (1993), a pinball game commissioned after Sega 's research determined that Casino Night Zone was one of the most popular levels in "Sonic 2". Following the completion of "Sonic & Knuckles", Yasuhara quit, citing differences with Naka, and went on to develop games for Sega of America. Naka returned to Japan with developer Takashi Iizuka to work with Sonic Team, and was reunited with Ohshima. A concept developed during "Sonic 2" production formed the basis of the Sonic Team game "Nights into Dreams", released for the Sega Saturn in 1996. The American team developed "Comix Zone" (1995), "The Ooze" (1995), "Die Hard Arcade" (1996) with Sega AM1, and  Sonic X-treme, which was canceled in 1996. STI was disbanded in late 1996 as a result of changes in management at Sega of America. Meanwhile, Cerny worked with Sony Interactive Entertainment and helped create the PlayStation franchises "Crash Bandicoot" and "Spyro the Dragon". Rereleases. "Sonic 2" has been ported to multiple platforms. In 1993, Sega released a version for arcade cabinets using its Sega Mega Play arcade system board. A Sega Saturn port included in the compilation "Sonic Jam" (1997) introduces an alternate difficulty mode that alters stage layouts and removes some levels for an easier experience. Other compilations  featuring the game include "Sonic Classics 3 in 1" (1995) for the Genesis; "Sonic Mega Collection" (2002) for the GameCube, PlayStation 2, and Xbox; "Sega Genesis Collection" (2006) for the PlayStation 2 and PlayStation Portable; "Sonic's Ultimate Genesis Collection" (2009) for the Xbox 360 and PlayStation 3; "Sonic Classic Collection" (2010) for the Nintendo DS; and "Sega Genesis Classics" (2018) for the Nintendo Switch, PlayStation 4, and Xbox One. "Jam", "Mega Collection", and "Classic Collection" include "Knuckles in Sonic 2" as a bonus. A remake of "Sonic 2" was released for Android and iOS devices on December 12, 2013 , and for Apple TV on March 24, 2016. The remake was developed from scratch by Christian "Taxman" Whitehead and Simon "Stealth" Thomley using the Retro Engine, previously used in Whitehead's 2011 "Sonic CD" remake. The remake adds enhancements such as support for widescreen displays, Knuckles as a playable character, time and boss attack modes, online multiplayer, additional multiplayer stages, and Tails's flying and swimming abilities from "Sonic the Hedgehog 3" (1994). It also restores Hidden Palace Zone as an optional, secret level. Whitehead redesigned Hidden Palace with input from Sonic Team, which informed him that STI had been  dissatisfied with the original level design. The Android version sold more than 100,000 paid downloads on the Google Play Store , and received more than 10million downloads by 2019, after it was made free-to-play. The remake was included in the 2022 compilation "Sonic Origins". A Nintendo 3DS port was developed by M2 and released as part of Sega's "3D Classics" line in Japan on July 22, 2015, and elsewhere on October 8. The port features stereoscopic 3D visuals, the option to switch between the game's regional variants, alternate sound and visual modes, and cheats. M2 was originally  hesitant to port the game, and it took the most effort of the "3D Classics" line due to its large size and elaborate levels. Several technical tricks, such as the interlacing in the multiplayer mode and the pre-rendering in the special stages, had to be reprogrammed so they could be retained. M2 also developed a Nintendo Switch port for the Sega Ages line, released in February 2020. It includes most of the additions from the 3DS version, as well as the option to use Sonic's Drop Dash ability from "Sonic Mania" (2017), a time attack mode, and "Knuckles  in Sonic 2". "Sonic 2" has also been rereleased on digital distribution platforms. It was made available for download on the Wii's Virtual Console on June 11, 2007, the Xbox 360's Xbox Live Arcade on September 12, 2007, the PlayStation 3's PlayStation Network on April 19, 2011, Steam on January 26, 2011, and for Nintendo Switch Online's "Expansion Pack" subscribers on October 25, 2021. These versions run via Genesis emulation, and the Wii and Xbox 360 versions allow users to play "Knuckles in Sonic 2" if they also own "Sonic & Knuckles". The Xbox 360 version sold  509,805 copies . An emulated version for iOS was released in April 2010, but was replaced by the remake in 2013; those who purchased the original version were offered the remake free. The Xbox Live Arcade, PlayStation Network, and Steam versions were delisted in 2022 ahead of the release of "Sonic Origins", a move that received criticism on video game preservation and consumer protection grounds. Legacy. Retrospective reception. "Sonic 2" continues to receive acclaim. Critics consider it an improvement over the first "Sonic the Hedgehog", saying it features greater level diversity and design, better graphics, and quality-of-life improvements. "GameSpot  said that Sonic 2" "does everything a sequel is supposed to do. It resolves many of the first game's shortcomings and incorporates a slew of minor upgrades that cumulatively amount to a fresh experience." "IGN" felt the emulated Wii rerelease was easy to recommend. "TeamXbox", "Eurogamer", and "Hardcore Gamer" said the level design, music, and fast gameplay still hold up exceptionally well, and "GamesRadar+" called it "the most user-friendly of all the "Sonic" games, beautifully presented and still a challenge if you want to complete it properly." Retrospective objects of criticism include the multiplayer mode and the implementation  of Tails. Reviewers disliked the image distortion brought about by the multiplayer mode's squeezed and flickering graphics, while they considered Tails a burden due to his interference in boss battles. Additionally, "Eurogamer" described the visuals of the special stages as "dreadfully blocky", and "IGN" felt that the inclusion of Tails in the stages was "detrimental at best" since he constantly hits bombs and makes the player lose progress. Some critics wrote that the late-game stages were difficult and complex, while "GamesRadar+" said that "[the game] could be criticized for 'playing itself'" during sequences when Sonic careens at high  speeds. The 2010 iOS and DS versions received middling reviews, with criticism for their quality and lack of multiplayer, but the 2013 remake was considered the definitive version. "TouchArcade" called it a "beautiful remaster" that would appeal to old and new fans and found it surreal to finally play the once-removed Hidden Palace in an official capacity. Critics praised the 3DS version for its implementation of the system's stereoscopic 3D and the added bonus features, with "Nintendo World Report" writing that the addition of cheats made difficult moments less frustrating. "Nintendo Life" was disappointed that the Switch version  did not include the 2013 remake's features and felt that M2 should have chosen a lesser-known game to port, given the copious number of "Sonic 2" rereleases. Nonetheless, "Nintendo Life" felt it was an excellent port and a "must-have" for first-time players. "Sonic 2" is frequently cited as one of the greatest video games of all time. Listing the game at number 71 in its Top 100 Games of All Time list in 2001, "Game Informer" wrote that "Sonic 2" was "the most challenging and finely polished "Sonic the Hedgehog" title." "Sonic 2" took first place  in a survey conducted by "Official Nintendo Magazine" to determine the fan-favorite "Sonic" game in 2010, and "GameZone" named it the second-best "Sonic" game (behind "Sonic 3") in 2011. "GamesRadar+" named "Sonic 2" the best "Sonic" game and the second-best Genesis game of all time (behind "Streets of Rage 2" (1992)) in 2017. In November 2017, Sonic Team head Takashi Iizuka said that he felt "Sonic 2" "really is the best of the classic "Sonic" series. The level design is just really, really solid... all of the [Sega] staff would say it was a great game for  Japanese tastes but also a great game for American tastes. "Sonic 2" really captured that global sense of game design and level design." Influence. "Sonic 2" was a major factor in keeping Sega competitive during the console wars of the fourth generation of video game consoles in the early 1990s. It boosted Genesis sales enough to solidify Sega as Nintendo's near-equal and cemented Sonic as a video game mascot on par with Nintendo's Mario. "Sonic 2" is credited for originating the concept of a concrete worldwide release date. The practice was unheard of before "Sonic 2" release  and became a widespread industry trend in the following years. "Sonic 2" introduced many elements that defined the "Sonic" franchise. The spin dash ability became a series staple, and Tails appeared in nearly every subsequent "Sonic" game and starred in two spin-offs, "Tails Adventure" and "Tails' Skypatrol", for the Game Gear in 1995. For the franchise's 20th anniversary in 2011, Sega released "Sonic Generations", which features reimagined versions of stages from across the series' history. The PlayStation 3, Xbox 360, and Windows versions contain remakes of "Sonic 2" Chemical Plant Zone and the Death Egg Robot boss fight , while the Nintendo 3DS version contains a remake of Casino Night. Additionally, a Casino Night-themed pinball minigame was released as downloadable content. "Sonic Mania" features reimagined versions of Chemical Plant and Oil Ocean, while "Sonic Forces" (2017) features a reimagined version of Chemical Plant. In the years since "Sonic 2" release, a number of prototypes have been leaked online. In 1999, "Sonic" fan Simon Wai discovered an early prototype containing the scrapped Hidden Palace, Wood, and Genocide City levels on a Chinese website and shared it with the Western "Sonic" fandom. The discovery played a significant role in the  development of the archaeogaming scene, as it encouraged players to datamine games and document prototype ROM images so they could understand how popular games were developed. Journalist Heidi Kemps presented the prototype to Naka during a 2005 "GameSpy" interview and he identified it as originating from a preview cartridge that had been stolen from a 1992 New York City toy show. A "Sonic" fan discovered the "Sonic 2" prototype featured on "Nick Arcade" in 2006 and raised over 1,500 to buy the cartridge and release the ROM image online. The "Nick Arcade" prototype, while primitive and unpolished, showed fans how  STI built the game atop the original "Sonic the Hedgehog". A high-definition (HD) fangame remake, "Sonic 2 HD", entered development for Windows and macOS in 2008. The project was canceled in 2012 after the release of a game demo that "Retro Gamer" described as "blighted by programming incompetence", due to high system requirements and digital rights management that inadvertently triggered antivirus software. However, the project was restarted by a new team in 2014. It is planned to feature additional levels, multiplayer modes, and the option to play as Knuckles. "Sonic 2" has also been noted for its active modding  scene that releases ROM hacks featuring new game mechanics and playable characters. Modders decompiled the source code of the 2013 "Sonic 2" remake in 2021, allowing it to be unofficially ported to any platform. Some design elements from "Sonic 2" feature in Studio Pierrot's "Sonic the Hedgehog" (1996) original video animation. The feature film "Sonic the Hedgehog 2" (2022) draws inspiration from "Sonic 2", though it is not a direct adaptation. The Death Egg Robot and Super Sonic appear in the film, while one of its posters recreates Martin's "Sonic 2" box art illustration. Sonic the Hedgehog 2