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 2Z is a palette and level layout hack of Sonic the Hedgehog 2 for the Sega Mega Drive/Genesis by Mystic. The objective is to make a harder version of Sonic 2 for experts who really haven't had a challenge in Sonic for years. In order to do this, Mystic made some exceedingly challenging levels, which are definitely going to make even a master Sonic player beg for mercy in a few sections.

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 3 Complete is a hack of Sonic 3 & Knuckles which aims to provide a much improved variant of the original game, with many new options and features, without straying from the original levels or gameplay. The inclusion of separate modes for Sonic 3, Sonic & Knuckles and Blue Sphere also make this a close cousin of the PC compilation Sonic & Knuckles Collection, albeit designed for the original 16-bit hardware.

Sonic the Hedgehog Genesis (Genesis) is a hack of Sonic the Hedgehog by Xenowhirl which attempts to recreate certain aspects of the Game Boy Advance Sonic 1port titled Sonic the Hedgehog Genesis.

Sonic the Hedgehog Mega Blitz is a hack of Sonic the Hedgehog (16-bit) made by SSE. It is named "Sonic the Hedgehog Mega Blitz (Sonic Mega Blitz)" Due to the fact that the hack is a "blitzed out" version of the original game.

Sonic the Hedgehog Megamix (commonly shortened to Sonic Megamix) is a work-in-progress multiperson disassembly modification of the original Sonic the Hedgehog videogame for the Sega Mega Drive / Genesis, developed by Team Megamix and more recently moved to the Sega Mega-CD. The game features the ability to play as one of five different characters: Sonic the Hedgehog, Mighty the Armadillo, Shadow the Hedgehog, Miles "Tails" Prower, and Knuckles the Echidna. It is an extensive reworking of the original game, featuring new art, music, abilities, layouts, and other things.