Sonic the Hedgehog 4: Episode I
Development began in June 2009 and lasted a year and a half. The game was conceived as a smartphone-exclusive spin-off before becoming a multiplatform, mainline "Sonic" installment. As a continuation of the Genesis "Sonic" games, "Episode I" features a simple control scheme, no voice acting, level design emphasizing platforming and momentum-based gameplay, and no player characters besides Sonic himself; however, it incorporates Sonic's design and abilities from later games like "Sonic Adventure" (1998). It was designed to appeal to both older "Sonic" fans who played the Genesis games and newer  ones who played more recent ones like "Sonic Unleashed" (2008). Producer Takashi Iizuka and composer Jun Senoue were the only "Sonic 4" developers who contributed to the Genesis games. "Episode I" was released in October 2010 as a downloadable game for iOS, PlayStation 3, Wii, and Xbox 360. Versions for Windows Phone, Windows, Android, and BlackBerry Tablet OS followed throughout 2011 and 2012. The game received moderately positive reviews and sold over a million copies in under a year. Critics described "Episode I" as a satisfying return to classic "Sonic" gameplay and praised the sense of nostalgia. Criticism was directed  at its physics engine, considered inferior to that of the Genesis games, and its short length. "Episode I" was envisioned as the first of an episodic video game trilogy. "" was released in May 2012, while "Episode III" was never made. Gameplay. "Sonic the Hedgehog 4: Episode I" is a side-scrolling platform game similar in gameplay and style to the 1990s "Sonic the Hedgehog" games for the Sega Genesis. The story begins shortly after the events of "Sonic & Knuckles" (1994). Sonic the Hedgehog parts with his friends, Miles "Tails" Prower and Knuckles the Echidna, to explore new territories on his  own. However, series antagonist Doctor Eggman—who survived his defeat in "Sonic & Knuckles"—resurfaces, refines some of his past robots, and initiates a plan to get rid of Sonic. "Sonic 4" is presented from a 2.5D perspective; although movement is restricted to a 2D plane, characters and objects are rendered in 3D. Sonic, the only player character of the single-player game, can move left or right to gain speed, jump, and roll into a ball to attack enemy robots. Sonic can also perform the "homing attack" from the 3D "Sonic" games; when in midair, he can lock on to robots  or objects and home in on them. In some cases, chaining homing attacks opens access to alternate pathways. The game takes place across four levels called zones, each split into three acts. Unlike the Genesis "Sonic" games, after completing the first act, the player can freely choose which zone to play via a world map. The levels are based on locations from the original "Sonic the Hedgehog" (1991) and "Sonic the Hedgehog 2" (1992), and feature elements such as slopes, bottomless pits, vertical loops, corkscrews, springs, and boost pads, as well as power-ups like shields, invincibility, and speed shoes . Some levels feature unique elements, like vines or pinball flippers and bumpers. After the player completes a zone's acts, they unlock a boss encounter with Eggman. Boss encounters feature Eggman piloting one of his robots, and the player must hit him eight times to defeat him. Completing all four zones unlocks a fifth and final level. Like other "Sonic" games, Sonic collects rings as a form of health: if the player is in possession of at least one ring and is hit by an enemy or hazard, they will survive, but their rings will scatter and blink before disappearing . If the player is hit with no rings, falls in a pit, or drowns, they lose a life, and will receive a game over if all lives are lost. If the player finishes an act with 50 or more rings, they will have the option to access a special stage. The special stages in "Episode I" are based on those from "Sonic the Hedgehog", in which Sonic is curled in a ball and bounces off the bumpers and walls of a fully rotating maze. The player must tilt the playing field to navigate Sonic through the maze within a time  limit, collecting rings to open gates and time bonuses along the way. Finishing the special stage rewards the player with one of the seven Chaos Emeralds. By collecting all seven, the player unlocks the ability to transform into Super Sonic, granting them invincibility and increased speed at the cost of one ring a second. Collecting the Chaos Emeralds also unlocks a brief post-credits scene that shows a silhouette of Metal Sonic, teasing the events of "" (2012). Players are also able to upload their game information to online leaderboards to compare level completion times and high scores. Each version of  the game is mostly identical, save for differences in screen size and resolution. For instance, the PlayStation 3, Xbox 360, and Windows versions support high-definition and widescreen displays, whereas the Wii version does not. Additionally, the PlayStation 3 and Wii versions both support their systems' respective motion controllers. The mobile versions can be controlled with either the accelerometers or virtual buttons on the touchscreen. Two levels exclusive to these versions are designed around the use of the accelerometers. Development. According to project head Takashi Iizuka, "Sonic 4" was conceived in January 2009; development began four months later and lasted  about a year and a half. Dimps, which had previously developed "Sonic" platformers for the Game Boy Advance and Nintendo DS, led development, with assistance from Sonic Team. Sonic Team's Toshiyuki Nagahara served as director. The only developers on the team who contributed to the Genesis games were producer Iizuka and composer Jun Senoue. The game was announced on September 11, 2009 under the working title "Project Needlemouse". Its proper title, "Sonic the Hedgehog 4: Episode I", was revealed on February 4, 2010, alongside the debut of in-game footage. Brand manager Ken Balough stated that "Sonic 4" was  conceived following fan requests for a return to classic "Sonic" gameplay. He acknowledged the divide between older "Sonic" fans who played the Genesis games and younger ones who played more recent games like "Sonic Unleashed" (2008), and said Sega needed to cater to both demographics. In an interview with "Nintendo Life", Balough said that "[w]hen we started discussing doing a 2D "Sonic" game, it just made sense that we would make "Sonic 4". It's a game fans have been asking about for years, and we felt we had the right team to make it." While Balough said the game  was always called "Sonic 4", according to journalist Kurt Kalata, "Sonic 4" was not conceived as a mainline, numbered "Sonic" game, but rather as a smartphone-exclusive spin-off called "Sonic the Portable" that took advantage of those devices' gyroscope functions. Kalata wrote that it was retitled "Sonic 4" at the behest of Sega's American branch and made a multiplatform release, and noted that one of the game's levels still features signs that say "Sonic the Portable". Iizuka noted that after "Sonic Adventure" was released in 1998, the "Sonic" series began to have a greater emphasis on speed . However, he also acknowledged many fans still enjoyed the Genesis games, as evidenced from their popularity on digital distribution platforms. With "Sonic 4", Iizuka was motivated to return to the classic "Sonic" style with modern technologies. To stay faithful to the original Genesis games, the developers chose not to include voice acting. The team began development using elements they considered vital to the "Sonic" series: a simple control scheme—with jumping and attacking controlled by a single button—and level design emphasizing platforming and momentum-based gameplay. To establish "Episode I" as a successor to the Genesis games, the developers  chose to revive those games' level locales to, as Iizuka explained, "tap into that nostalgia factor. Essentially we wanted people to recognize this was a continuation from the [Genesis] era "Sonic"s." While the content in all versions is mostly the same, two levels in the mobile version were replaced in the console releases. These two levels were supposed to be retained across all releases, but they were designed around the use of a smartphone gyroscope, and the team did not think they translated well to a console. One new addition was Sonic's homing attack from "Sonic Adventure"; Iizuka said  the team "wanted to add that excitement of performing continuous attacks" and felt it "add[ed] to the classic-style gameplay by providing a new means to discover routes in the sky". Though a return to the classic "Sonic" formula, "Sonic the Hedgehog 4: Episode I" does not reuse Sonic's original design, instead retaining his post-"Adventure" design. Iizuka reasoned this was because the game was not a remake. Following the project's announcement, in January 2010 Sega began a countdown with a list that discounted potential playable characters. When fans answered trivia questions, the list got whittled down, and culminated  with the reveal that Sonic would be the only playable character. Iizuka said this decision was made because the team wanted both old and new fans to be able to enjoy the game. The decision to scale back the series' extensive cast was also identified as a way to return to the series' roots. Despite this, the post-credits scene teases the reintroduction of Metal Sonic, who had not appeared in a "Sonic" game for years. Balough stated that fans had been asking Sega to bring back Metal Sonic for years, and that the post-credits scene was added to  keep players excited for "Episode II". Senoue only composed some tracks for the Genesis "Sonic" games, but for "Sonic 4", he was responsible for creating all the music and sound effects. The music was written to replicate the style of the Genesis "Sonic" games because, according to Balough, the developers wanted the game to feel "like a genuine extension of the first three "Sonic" games". Senoue was involved with the project early on, when Iizuka approached him to ask him to compose. Senoue said that he attempted to compose the tracks as if he had been composing them for the  Genesis, using as few notes as possible. He did not use any FM sound tapes, although he did unsuccessfully attempt to find an old Genesis development kit. Senoue attempted to compose tracks "with a similar beat or similar tempo" to those from "Sonic the Hedgehog" and "Sonic the Hedgehog 2". Senoue had fun working on "Episode I" and said his favorite track was the first level's, although Nagahara hated it and tried to persuade Senoue to compose a replacement tune. Eggman's theme in "Episode I" had originally been composed for "Sonic 3D Blast" (1996), but went unused in  that game. Release. "Episode I" was originally scheduled for release in July 2010, a timeframe Sega announced in February 2010. Months before the game's release, a prototype version was made available to users of the Xbox 360's game testing service PartnerNet. Screenshots and footage were leaked and widely distributed across the internet, and PartnerNet had to be temporarily shut down as a result. Though some video game journalists responded favorably to the leaked materials, fans reacted negatively. In May 2010, Sega announced that "Episode I" had been delayed to late 2010 in response to both internal and fan  feedback; Iizuka later clarified that the delay was done so the developers could replace the mobile-exclusive levels with ones better suited for consoles. "Episode I" was released on October 7, 2010, for iOS. Releases for other platforms soon followed: the Wii version was released via WiiWare in North America on October 11 and in Europe on October 15; the PlayStation 3 version was released via PlayStation Network in North America on October 12 and in Europe on October 13; and the Xbox 360 version was released via Xbox Live Arcade on October 13. Other releases included a Windows Phone  version on June 15, 2011; a Windows version via Steam on January 19, 2012; an Android version on January 25, 2012; and a BlackBerry Tablet OS version on July 20, 2012. Additionally, both "Episode I" and "Episode II" were released for the Android-powered Ouya on July 9, 2013. In April 2016, the iOS version was updated for the first time in three years to modernize it for newer devices. Changes included support for widescreen and Retina displays, more detailed character models, and refined textures. The iOS version was initially split into separate versions for iPhone and iPad; the update  discontinued the iPad version and made the iPhone one a "universal" application, meaning it works across all iOS devices. Later in 2016, the Xbox 360 versions of "Episode I" and "Episode II" were added to the Xbox One's catalog of backward-compatible games. Reception. "Sonic the Hedgehog 4: Episode I" received generally positive reviews, according to review aggregator Metacritic. "IGN" Hilary Goldstein gave the game a score of 8.0 and an Editor's Choice award, calling it "short but sweet and well worth downloading." "GamesRadar+" Justin Towell gave it a score of 9/10, calling it "deserving of the name , "Sonic the Hedgehog 4"." "1UP.com" Kat Bailey gave it a B rank, praising the game's speed while criticizing some occasional poor design, such as boss battles and puzzles. GameTrailers gave it a 7.5, calling it a worthy investment for "Sonic" fans. "Digital Spy" gave it three out of five stars, with reviewer Liam Martin answering the question of whether or not it lived up to its hype: "Despite some issues with the size of the game and its difficulty (it's very easy), the answer is yes, but only just." "Eurogamer" Ellie Gibson gave it a 9/10, calling it  gloriously fun and "brilliantly paced." The game's physics were met with major criticism, with the general consensus being that they were inferior to the momentum-based physics from the Genesis games. On YouTube, hundreds of gameplay videos were posted by fans showcasing several oddities. The game was a commercial success, selling over a million copies across all platforms by 2011, according to Sega of America CEO Mike Hayes. Legacy. "Episode I" was envisioned as the first installment of an episodic video game trilogy. Shortly before "Episode I" release, Balough confirmed that Sega had planned the entire "Sonic 4" story . While he did not confirm the number of episodes, he said "[they] will definitely make up a larger game. After completing them all, you'll have experienced a larger overall story arc that lives up to the epic nature of earlier "Sonic"s." In August 2011, Iizuka stated that "Episode II" would not be released until 2012 (over a year after "Episode I") so Sonic Team could focus on "Sonic Generations". Ahead of "Episode II", Sega rereleased "Sonic CD" (1993) for modern consoles, and advertised it as a prequel to "Sonic 4". "Episode II", released in May 2012, reintroduces Tails and  Metal Sonic, and follows Sonic and Tails as they attempt to prevent Eggman and Metal Sonic from relaunching the Death Egg. Fan input from "Episode I" played a significant role in the development of "Episode II", as the developers worked to address aspects fans took issue with, such as the physics engine. "Episode II" was released on most platforms that "Episode I" was available on, although the Wii version was canceled due to hardware constraints. Players who own both episodes on a single platform unlock the ability to play as Metal Sonic in "Episode I" levels. In March 2012, Iizuka  announced that Sega did not plan to continue "Sonic 4" beyond "Episode II". In 2015, Australian developer Christian Whitehead said that he had been offered the opportunity to develop "Episode III" with Sega Studios Australia before that division was shut down, and he instead worked on remasters of "Sonic the Hedgehog" and "Sonic the Hedgehog 2" between 2012 and 2013. He said that while it was possible that "Episode III" could eventually be made, it was unlikely. Whitehead would go on to lead the development of "Sonic Mania" (2017), which, like "Sonic 4", acts as a sequel to the Genesis  Sonic games. "Sonic 4" and "Sonic Mania" were frequently compared, with journalists viewing "Sonic 4" unfavorably in contrast to "Mania".