Sonic the Hedgehog 2 (ソニック・ザ・ヘッジホッグ2 Sonikku za Hejjihoggu Tsū?) is a platform video game developed by Sonic Team and Sega Technical Institute, and published by Sega. 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,[3] who must stop the series antagonist Dr. Ivo Robotnik from stealing the Chaos Emeralds to power his Death Egg space station.Originally released for the Sega Genesis/Mega Drive in 1992, the game was a critical and commercial success, 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.

Sonic 2 Long Version (which is released alongside Sonic 2 & Knuckles Long Version) is a more complete version of Sonic 2, which makes it somewhat similar to Sonic 2 Delta. This hack features four levels originally scrapped during Sonic 2's development. No levels have been changed, only added. This hack was written in hex, without the aid of any special hacking programs, because the creator uses a Mac, and no hacking tools had been released on that platform at the time of development.

Sonic 2 XL is a hack of Sonic the Hedgehog 2 for the Sega Mega Drive/Genesis by Captain Bozo and Ranger. Rings are replaced with onion rings, and Sonic becomes fatter after eating them.

Sonic the Hedgehog 2: Pink Edition is a character swap hack of Sonic the Hedgehog 2 for the Sega Mega Drive/Genesis, with Amy Rose and Cream the Rabbit replacing Sonic the Hedgehog and Tails respectively. Amy Rose's sprites are designed after her modern look. Amy Rose with classic-style sprites is available to play in the Amy Rose in Sonic the Hedgehog 2 hack. The game was modified by Sonic Retro Member E-122-Psi, with additional programming and coding by other members including MarkeyJester, MainMemory, FraGag, Selbi, and Hayate. Most programming unique from Amy In Sonic 2 such as Cream the Rabbit's gameplay was implemented by Flamewing.

Sonic the Hedgehog 3 (ソニック・ザ・ヘッジホッグ3 Sonikku za Hejjihoggu Surī?) is a 1994 platform video game in the Sonic the Hedgehog series for the Sega Genesis. It was developed in the United States by members of Sonic Team working at Sega Technical Institute, and was published by Sega, debuting worldwide in the first half of 1994. The game is a sequel to the Sonic the Hedgehog 2 for the same system and follows on directly from the end of the game, in which Sonic defeated his enemy, Dr. Robotnik; crash-landing on a floating island, Sonic encounters new character Knuckles the Echidna, and must once more retrieve the Chaos Emeralds while also working to stop Dr. Robotnik from relaunching his ship, the Death Egg.The game is closely tied to its direct sequel Sonic & Knuckles, as the two games were originally developed as a single game until time constraints and cartridge costs forced them to be split into two interlocking parts.

Sonic the Hedgehog 3 (Nov-3-1993 prototype)...You can get more information's about this prototype in the hidden palace website, here is the link:https://hiddenpalace.org/Main_Page