Sonic 1 The Blue Blur is a hack of Sonic the Hedgehog for the Sega Mega Drive/Genesis, created by Scwha. It gives each Zone totally new palettes and layouts, with the latter designed to be more difficult than those of the original game.

Sonic 1: The Special Stages is a hack of Sonic 1 by SonicVaan. This hack removes standard Sonic gameplay and replaces it with the Special Stages which normally were only accessible by the Giant Rings at the end of each stage.The actual special stage layouts have been touched for every stage.This hack is actually on hold. Future releases are not to be expected.

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 Hedgehog on the Sega Mega Drive. It began in 2005 with the simple purpose of being a generic Sonic 1 for Sega Genesis with increase difficulty and revamped versions of the original levels. But now, it's going to present a completely new gaming experience with a new style of level layouts full of paths everywhere among new enemies, new objects, new character abilities, new menus, completely different styles of the Sonic 1 special stages and much more!Credits and Special ThanksMistergambit for his Spring Yard Zone and Labyrinth Zone level art used in the game.Tweaker for his information regarding music importing, bug fixes and the speedcap removal.HPZMan for the new sound driver instruments and the dynamic tile-set system.Selbi for some new exclusive ASM things and improvements.Master3k for sending and fixing some music.nineko for creating the xm3smps tool which was essential for the creation of some songs. Special credits to him for the different songs per act system used.SCAA for their art.Puto for his tutorial to add Spin Dash.FraGag for his tutorial to fix the spike bug.SonicVaan for beta testing.HCKTROX for the lead programming and bug fixing.GenesisFan64 for the save screen menu, for some fixes related to the fade-out and others.MarkeyJester for lots of important code and a whole load of others.Irixion for beta testing.PsychoSk8r for his the dynamic palettes tutorial.Esrael for fixing essential things in the new sound driver.Prilix Bõkun for bug searching and beta-testingEstlib for various art stuff related to levels and for additional help with creation of gimmicks and objectsDJ. Joker27 for his very big importance in specific level and misc musicMighty Arnold for additional support with beta-testing and level layout designKenny0989 for additional support in the music department Special credits to Harder Project's Team by all the useful exclusively things used in the project.