Sonic 1 Color Contrast is a hack of Sonic the Hedgehog for the Sega Mega Drive/Genesis by TheInvisibleSun. It features new palettes and art, modified zone layouts, audio modifications, and various other special additions.

Sonic 1 Dragon Edition is is a modification of Sonic 1 made by DragonWolfLeo that focuses on original art and music to make brand new zones, along with other changes to enhance gameplay.

Sonic 1 Easy mode is port of Sonic 1's Easy mode from the Sega Saturn game Sonic Jam. Easy mode uses completely different level layouts. The level order is also different and some levels are omitted completely (but are still playable using level select).

Sonic 1 Flash Flood is a ROM hack of Sonic the Hedghog that features new palette, audio, zone layout and special stage modifications, in addition to new gameplay mechanics. Flood waters rise and recede at random all over the island, significantly changing how the island is navigated. Can you make it through?Features:Level Design - In addition to the rain effect and water palettes, level layouts are tweaked to account for water physics.Marble Zone has altered lava physics, and Acts 2 and 3 have new shortcuts.Being entirely underground, Labyrinth Zone has been affected a bit...differently by the change in weather.Goggles Monitors - These take the place of air bubbles, and are thus unlimited. Use as many as you need!Badnik Behavior - The rain and flooding is even affecting Eggman's robots and hazards, causing them to malfunction! Some are even enhanced by the chaotic weather. Strangely, most fire-related hazards (such as flamethrowers and fireballs) remain unaffected, defying all logic.Special Stages - New special stage gameplay style, with art and music changes. Get Yellow Rings!Water Physics - Some general quality of life improvements to the water physics, and bug fixes are included here (with a few exceptions, for gameplay reasons).Level Select - Available upon pressing start, no code required. Feel free to check out any zone or special stage at your leisure.Known Bugs:Minor graphical bug in the special stage background, and on the results screen.In the Special Stages, blocks at the edge of the screen being loaded in flicker, due to the amount of objects.Level art mapping glitches crop up on rare occasion.Labyrinth and Scrap Brain's palette cycles are bit buggy at the moment.There are a couple of lingering walk-jump bugs here and therePlanned FeaturesImproved object optimizationImporting Sonic 2-3's child sprite systemUnderwater sound/music modeEven more environmental effects.More significant changes to bosses, Final Boss, etc.

Sonic 1 NAC Tiny Version (Tiny as in short version) is a hack based on Sonic 1 made by Campbellsonic is a simple but advanced sonic 1 hack that has different events and concepts with in each level. Therefore making each level different and unique to the standard level edits that you find in must hacks, especially some of mine. Hack Story line:One day sonic decided to take a break from his friends and the stress that he has been going through, and went back to south island. however when sonic had arrived at south island he noticed something was different, everything seem to have changed colour and seemed to be a lot darker then it use to be, And so he decided to explore. After spending 10 minutes exploring the changes; sonic noticed the that the badniks that he destroyed before had reappeared in green hill zone. Then sonic realized that robotnik was back to no good once again and goes to save south island once again. Level Information:You may notice that all of the main levels have a wall that seems to be unbreakable at the end of the level, this is because your required to find and hit an "S" monitor in order for that wall to become breakable and before your able to finish the level. Act 2 of the main green hill zone will start off normal but then you will given a platforming challenge. Act 3 of the main green hill zone is a auto running level inspired by sunset park act 3 from sonic triple trouble, where you have no control over sonic's speed or direction he is running in, all you can do is make sonic jump.Credits:Beta Tester: Sarah Mckinney (KosmoF)

Sonic 1 Remastered is a hack of Sonic the Hedgehog (16-bit) for the Sega Mega Drive/Genesis by Puto. Unlike most other hacks, the officially released version 1.1 isn't a level art/palette/layout hack as much as an "additional features" hack done in ASM. One of the major additions to the game is added with the choice of using Sonic or Tails throughout the game (selecting a character is done at the title screen). There also exists a version 2 hack which was leaked without Puto's permission, although he later gave permission to upload it onto the wiki.

Sonic 1 Special Version is Sonic the Hedgehog hack made by EditChris.This hack add new level layouts, New Art, A lot of ASM changes/add, MegaPCM driver improved and a lot of music added.