Players control Sonic as he attempts to stop Doctor Robotnik from stealing the Chaos Emeralds to power his space station.

Like the first Sonic the Hedgehog (1991), players traverse side-scrolling levels at high speeds while collecting rings, defeating enemies, and fighting bosses.

The development suffered setbacks, including cultural differences between the Japanese and American staff, and numerous levels were cut due to time constraints and quality concerns.

A number of Sonic 2 prototypes have leaked since the release; the first, discovered in 1999, played a significant role in the development of a game datamining community.

[1] It features a story similar to the first Sonic the Hedgehog's (1991):[2] Doctor Robotnik, a mad scientist, seeks the Chaos Emeralds to power his space station, the Death Egg,[3] and traps the animal inhabitants of West Side Island in aggressive robots.

[7] The acts are larger than the first game's,[8] and the player navigates them at high speeds while jumping between platforms, defeating robot enemies, and avoiding obstacles.

[2] The player starts with three lives, which they lose if they are hit without a ring, fall down a pit, get crushed, drown, or reach the 10-minute time limit; they receive a game over if they run out.

The success meant that a sequel was inevitable, but shortly after the release, the team disbanded: 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,[23] while Yasuhara moved to America to join Mark Cerny's California-based Sega Technical Institute (STI).

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.

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.

[44] The special stages, designed by Shinobi (1987) director Yutaka Sugano,[38] were created from pre-rendered 3D polygons, video of which was compressed and halved vertically and horizontally to fit in the game cartridge.

He said that the situation was severe because Sega of America was "betting everything" on Sonic 2, but the STI staff did not display any stress and remained optimistic that the project would be finished.

Managing director Daizaburou Sakurai contacted Sega Enterprises president Hayao Nakayama, who allowed the team to double the ROM size to avoid a delay.

[32] Yoshii felt that despite the staff conflicts, the bug-checking made developing Sonic 2 in the US worth it, as Sega of America's process was much more thorough than the one in Japan.

[61] 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.

[42] An early version appeared on the Nickelodeon game show Nick Arcade several times, including in a competition between the Clarissa Explains It All (1991–1994) stars Melissa Joan Hart and Jason Zimbler.

[104][105] Mega said that the ability to race against a friend rather than just the in-game timer added substantial depth,[105] and EGM said it would double the amount of fun players would have.

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.

[136] The Xbox Live Arcade, PlayStation Network, and Steam versions were delisted in 2022 ahead of the release of Sonic Origins,[153] which received criticism on video game preservation and consumer protection grounds.

Game Informer wrote that it "expanded the formula in myriad ways, giving Sonic new moves like the spin-dash, bigger stages to explore with more branching paths, and more inventive boss battles.

[1] TeamXbox, Eurogamer, and Hardcore Gamer said the level design, music, and fast gameplay still hold up exceptionally well,[8][17][165] 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.

Reviewers disliked the image distortion brought about by the multiplayer mode's squeezed and flickering graphics,[1][164] while they considered Tails a burden due to his interference in boss battles.

[136][171] 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.

[136] Critics praised the 3DS version for its implementation of the system's stereoscopic 3D and the added bonus features,[8][2] with Nintendo World Report writing that the addition of cheats made difficult moments less frustrating.

[172] 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.

[50] Interest in Sonic 2's development began after players discovered that Hidden Palace, which appeared in magazine previews, was missing from the released game.

[179] 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.

The Nick Arcade prototype, while primitive and unpolished, showed fans how STI built the game atop the original Sonic the Hedgehog.

[64] In 2023, Cifaldi's Video Game History Foundation (VGHF) obtained design documents from one of Sonic 2's artists, Tom Payne, which included the Genocide City sprites, palettes and level layouts.

[192][193] 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.