Sonic The Hedgehog: The Lost Worlds is a hack of Sonic the Hedgehog 2 by ExecByte. This hack features all of the zones that were cut from Sonic 2 during development. Some zones have been ported from the Sonic 2 Simon Wai prototype and then finished up, and some have been created based on magazine pictures and information from interviews with people who worked on Sonic 2.

Sonic the Hedgehog - Westside Island is a palette and layout hack of Sonic the Hedgehog for the Sega Mega Drive. All levels have new layouts, new names and new palettes and the bosses have been made harder. In addition, the level select has been edited and you can now only start on Act 1 of each level from here. If you want to play Sonic 1 but with a new change of pace, this could be what you are looking for.

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 And The Mystic Gems (previously known as Sonic 1 Harder Levels) is a hack made by Eduardo Knuckles and his team Harder Project of Sonic the Hedgehogon the Sega Mega Drive/Genesis. The hack adds to the game a lot of new features such as the three known main playable characters, a checkpoint monitor, customizable level music playlist, a sweet and clear save data select menu, difficulty selection, a unique music menu and some other additional menus and screens which gives to the game a completely new gameplay experience.

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: Isle of Magnetic Artifacts is a sonic hack made By Neo Team Kyukyokuis a hack which aims to overhaul Sonic 1 using a Japanese-inspired aesthetic. The main feature of this demo is Blossom Gardens Zone, the resting area of the isolated, star-god worshipping Kuratranos tribe. BGZ is a fast-paced experience littered with swift-acting enemies, height-granting gimmicks, driving music, and advanced graphical effects. This new zone can be traversed with three playable characters: Sonic the Hedgehog, Miles "Tails" Prower, and Knuckles the Echidna. Sonic, in particular, features a set of unique sprites, the dropdash ability, and a new companion: Abbey the Flicky. Abbey can pick up nearby rings and circle potential targets for Sonic, including hidden monitors.Neo Team Kyukyoku MembersAngelKOR64: Character programmingChron D: Music arrangementDeltaWooloo: Level layouts, music arrangement, object ports, programming, sound effectsDaxKatter: Music arrangementDio-ZX: Character art, object artDrag109: Level artfuzzy: Level art, programmingiced t: Level art, object artInferno: Level layoutsInktitious: Level artJerry: Level layoutsKatKuriN: Level artKGL: Level layoutsKurk: Team Leader, level layouts, music arrangement, music compositionManiacShard: Object artNaotoNTP: Object artProjectFM: Creative direction, level art, music arrangement, music composition, programming, story planningRaendom: ProgrammingRivet: Programmingtwo^: Concept artyami: Level layouts, music compositionFormer MembersAmzroSevca: Concept art, story planningGemini0: Former team leader, general art, level layouts, programmingjrm1007: Concepts, object artHaz Rabbit: Concept art, programminglavagaming1: ProgrammingNotQuiteHere: Music arrangementpoly: Logo, music arrangementMr. Gandy: Character artXGSOAP: Character artPlaytestersAccelBladeOfChaosCertainly GlitchyCosmic EternityDaxKatterfengishGGK912Hooded EdgeKCEXEKNIJohnMattyMeara BlanchetteMCTravisYTProfessor RendererPXSleekflash-16Sr ParadoxosoapyyTheInvisibleSunUnusualSeekerResourcesAsuharaMoon: Wind-Up Koi spritesAURORA☆FIELDS: SMPS2ASM and AMPSCartoonsAnimate22: Tails and Knuckles spritesCuckyDev: GHZ ball baseflamewing - Ultra DMA Queue + optimized Kosinski (improved by vladikcomper and MarkeyJester) and Enigma decompression codeLone Devil: Metal Sonic spritesMainMemory: SonLVL and Drop Dash programming guideMarkeyJester: DualPCM and sound testMikel Nash: Sonic 3-style super sonic spritesObserver: Sprite ripsShibaMayo: ShibaSaturn spritessnkenjoi: Flex 2The Eighth Bit: Space Queens MIDITheOneMusaab: Sonic 2: The Alternative Spritestildearrow: FurnaceTeck: Super Mario Land - Ending Theme MIDIvladikcomper - optimized Nemesis decompression codeValleyBell: mid2smps, SMPS Converter, SMPS Research PackVladislavSavvateev: DMF2AMPSAssets From:Capcom no Quiz Tonosama no YabouCave StoryFreedom PlanetHigh Seas HavocMega Man SeriesMichael Jackson's MoonwalkerRistarSangokushi Retsuden: Ransei no EiyuutachiShinobi IIISonic SeriesTouhou Project Series

Sonic the Hedgehog Revelation (or Sonic Revelation) is a hack of Sonic 1 by Animemaster. This hack has many features and will continue to increase them, while the product is under way. It also plans a new zone, made of instruments known as music land. Although the creator hasn't decided on whether the art would be good enough yet. The hack contains the three hedgehogs Sonic, Shadow, Silver as they join to face Eggman once again.