Mighty the Armadillo is a hack of Sonic the Hedgehog for the Sega Mega Drive/Genesis by Yuski. The hack features Mighty the Armadillo, who appeared in bothSegaSonic Arcade and Knuckles' Chaotix. Features include new art, palettes and layout for Green Hill Zone.Mighty the Armadillo is one of the oldest ROM hacks, with work on it starting in June 2000 with the help of Gen-SMS. It has since been discontinued in order for Yuski to work with Esrael on Sonic Gaiden.

Mighty the Armadillo in Sonic the Hedgehog (aka Mighty in Sonic 1) is a hack of Sonic 1 by E-122-Psi, starring Mighty as the playable character instead of Sonic the Hedgehog. The game is modified to use Mighty's sprites in place of Sonic's, along with several modifications to the player's stats and abilities.

Flink (released in North America as The Misadventures of Flink), is a 2D scrolling platform video game developed by Psygnosis.The Amiga CD32 and Sega CD versions are reliant on CD-ROM media to store large levels, highly detailed graphics, and high-quality music. The Mega Drive version is a cut-down version.Flink is one of the few Amiga CD32 titles not to see a release for the Amiga home computer system, on which the CD32's hardware was based. The majority of titles released for the CD32 were essentially the versions developed for Amiga home computers, taking only minor advantage of the CD-ROM medium with extra levels, CD audio, and/or FMV sequences.The creators, Erwin Kloibhofer and Henk Nieborg, were also responsible for the games The Adventures of Lomax and Lionheart.

Motobug the Badnik in Sonic the Hedgehog (aka Motobug in Sonic 1) is a hack of Sonic the Hedgehog for the Sega Mega Drive, by Polygon Jim. As its title suggests, in this hack the main character Sonic the Hedgehog is replaced by Motobug, one of Dr. Robotnik's badniks.So far, some of Sonic's main sprites and animations have been replaced by those of Motobug, Motobug's speed has been decreased (except when powered-up by aSpeed Shoes monitor, which are more numerous), and the sprites of Roller badniks in Spring Yard Zone have been replaced by those of Sonic (referencing a common interpretation by fans that Roller is a robotic impersonation of Sonic, something that officially appeared in later games in the form of Metal Sonic and various others).Of the first release, Polygon Jim stated that he had only tested and confirmed Green Hill Zone (Acts 1-3) for completability. However, upon testing, Katelynn andRGamer2009 reported that other Acts are completable, including:Marble Zone Act 1Spring Yard Zone Acts 1 and 2Labyrinth Zone Acts 1 and 2Star Light Zone Acts 2 and 3Final Zone

Mr. Needlemouse is a hack of the original Sonic the Hedgehog game for the Sega Mega Drive / Genesis, by MKAmeX. It replaces Sonic the Hedgehog with one version (arguably the strangest) of his designer Naoto Ohshima's early prototype of the character, Mr. Needlemouse. Planned features include a complete overhaul of the game's graphics to resemble early concept art, and perhaps new music.

Mr. Nutz is a side scrolling, 2D platformer video game published by Ocean Software. It was first released for the Super Nintendo Entertainment System in 1993[citation needed], then later released for the Mega Drive and Game Boy in 1994[citation needed], then Sega Channel in 1995, followed by Game Boy Color in 1999, and Game Boy Advance remake in 2001. The player controls the one player character, Mr. Nutz an Anthropomorphic red squirrel wearing shoes, gloves and a cap through six themed levels. The end goal is to stop Mr. Blizzard, a yeti, who is the final boss and is trying to take over the world by using his magic powers to turn it into a mass of ice. The game shares similarities with other platformers of the same time, being that jumping is the main technique used in the game to navigate both fixed and moving platforms and defeat or avoid most enemies. Ammunition, in the form of nuts, can be collected and thrown at enemies. Ocean released in 1994 another game on the Amiga under the name Mr. Nutz: Hoppin' Mad. Developed by Neon Studios, it featured the same titular character but with different, faster and more wide-open gameplay, unrelated levels and enemies, another story, and a large overworld map instead of a linear path to follow in a mini-map. This game was also going to be released for the Sega Mega Drive in 1995 as Mr Nutz 2, but it got shelved. A playable build exist, leaked in the form of source code and compiled upon.