Sonic Classic Heroes is a ROM hack for the Sega Mega Drive / Genesis that is the result of a collaboration between flamewing and ColinC10, combining their respective hacks Sonic 2 Heroes and Sonic 1 and 2. It therefore is a single ROM that offers the entire campaigns of Sonic the Hedgehog and Sonic the Hedgehog 2, either alone or together; and enables the player to play as many characters such as Sonic, Tails, and Knuckles. The hack is named due to the ability to control a team of characters, which is reminiscent of the more recent 3D game Sonic Heroes.The hack is built on Sonic 2's engine, which has been enhanced by both flamewing and ColinC10 to have new features. These include: multiple gameplay elements from Sonic 3 & Knuckles, such as element shields and character-specific abilities; the ability to save progress, scores, etc. to SRAM (something rarely implemented in Sonic 2, with the other notable example being Esrael's Sonic 2 Delta); various bug-fixes and improvements to the mechanics of the original games; and many more features, both implemented and planned.

Sonic the Hedgehog Spinball, or Sonic Spinball (ソニック・スピンボール Sonikku Supinbōru?), is a pinball video game in the Sonic the Hedgehog series. It was originally released for the Sega Mega Drive/Genesis in 1993, and later ported to the Sega Game Gear and Sega Master System in 1995.The term "Spinball" is a portmanteau on pinball and "spin dash", a move Sonic performs. It, along with Dr. Robotnik's Mean Bean Machine were the only two Sonic games released to use characters and elements from the Adventures of Sonic the Hedgehog and Sonic the Hedgehog cartoons.

Sonic the Hedgehog 2 (Japanese: ソニック・ザ・ヘッジホッグ2, Hepburn: Sonikku za Hejjihoggu Tsū) is a platform video game developed by Sonic Team and Sega Technical Institute, and published by Sega for the Sega Mega Drive/Genesis console. It was released in Japan on November 21, 1992 and in North American and European markets on November 24 the same year. The game is an installment in the Sonic the Hedgehog series, and focuses on the protagonist Sonic the Hedgehog and his friend, a fox named Miles "Tails" Prower, who must stop the series antagonist Dr. Ivo Robotnik from stealing the Chaos Emeralds to power his Death Egg space station.Development of the game began in November 1991, two months later than originally intended, because Sega of America initially felt that it was too soon for a sequel. Both the American and Japanese Sonic Team staff contributed to developing the game; art director Tim Skelly designed the appearance of the game's new 3D Special Stages, which were based on an earlier tech demo created by Yuji Naka. The staff increased the speed of Sonic the Hedgehog 2 in comparison to its predecessor. As with the first installment, the soundtrack was composed by Masato Nakamura.The game was a critical and commercial success upon release, with critics praising it for building upon the original Sonic the Hedgehog game. The game has sold over 6 million copies, making it the second-best-selling game on the console, behind only its predecessor in the Sonic series. Since its initial release, the game has been released in several compilations and download releases for various platforms, which were also generally positively received.