

Sonic 1 on Bird Hill Island is a ROM hack of the original Sonic the Hedgehog for the Sega Genesis. The hack features extensive level redesigns, including reimagined zones like Bird Hill (Green Hill), Mysterious Marble, and Bird Park (Spring Yard).

Sonic the Hedgehog & Ashuro is an awesome ROM hack based on the classic Sonic the Hedgehog. Created by Ashuro from SSRG (Drakughost), the game features 2 characters and 2 universes on one single screen. The game features custom and special stages with 3 acts that take place during the different time of the day. In this game, you will control both Sonic and Ashuro. The two characters have similar movement but use a different approach on various obstacles like water and high places. If you can collect 50 coins during the gameplay, you will transform into a more powerful form. Good luck!

Sonic 3: Angel Island Revisited (Sonic 3 A.I.R.) is an unofficial port of Sonic 3 & Knuckles for Windows PCs. It very closely resembles the original game, but adds features you would only expect from a modern fan game engine - including full support for 16:9 widescreen display, alpha transparency effects, and smooth 360° rotation.

Platform / Adventure / Indie / Action / Science fiction
Sonic Robo Blast 2, abbreviated as SRB2, is a fan game for Windows and DOS platforms. It is a 3D platformer developed by a group called Sonic Team Junior, using a modified version of the Doom Legacy source port of Doom, to allow for such things as optional analog control and true room-over-room (something not possible in the standard Doom engine), as well as the standard gameplay elements Sonic games are known for. It has been in the works since 1998 and is currently nearing completion, though several parts of the game are still missing. Sonic Robo Blast 2 is closely inspired by the original 2D Sonic games for the Genesis and attempts to recreate a game with this style in 3D, though it also borrows elements from the current Sonic games, such as Sonic's signature Air Spin Attack. Entirely original to SRB2 is its Multiplayer mode, a variation of classic first-person shooter games with Sonic elements. Due to being built with a modified Doom Legacy engine, the game is also very easily customizable. Custom levels, characters and even source code modifications can be created with the help of external editors.

The citizens of Mobius just can't seem to catch a break. Dr. Robotnik (AKA Eggman) is yet again up to his no good tricks. Factories and pollution are spreading like wildfire as he's once again trying to take over the world. Fortunately, the Sonic Heroes are never at rest, and once again wage their battle to defeat Eggman's evil forces. However, the heroes have landed in double jeopardy. Eggman's madman descendant, Eggman Nega, has escaped from the Ifrit's dimension, and is wreaking his usual havoc in an effort to destroy the world. He's even captured Eggman's top three lieutenants, the ruthless Team Metallix, and reprogrammed them to do his even more evil bidding. Unlike previous instances of Nega's destruction, Eggman is not fazed. He figures that once he's in control of the world, he can take care of Eggman Nega as he pleases. Unfortunately for Eggman, Sonic the Hedgehog isn't having that. Before he can decide who to dispatch where, he receives a call through the communicator Tails gave him. The message: someone's already on the case. Not just someone, but someones! Apparently, Sonic's very own sister, Sonia the Hedgehog has already caught wind of Nega's evil and is out to stop him. Sonic is a bit eased, knowing full well of his sister's strength and agility. She also lets him know that she has found and teamed up with a mysterious young hedgehog who can move things with his mind. Sonic instantly recognizes that Sonia is with his newest ally: Silver the Hedgehog. Silver has once again traveled through time to ensure that the future is free of Nega's tampering (though he really ought to just stay here in the present, you know). Knowing that the two hedgehogs are more than capable of handling the situation, Sonic leaves it to them, and resumes dealing with Eggman. Eggman Nega is well aware that Sonic is busy with his dimwitted ancestor. However, he'd do best not to overlook a certain factor. The S Factor, Sonia and Silver! It's up to you to lead the unlikely tag team of the physically powerful Sonia, and the psychokinetic Silver on their quest to right the wrongs of the evil Eggman Nega!

Mega Man X in Sonic The Hedgehog 2 is a ROMhack/mod of Sonic The Hedgehog 2 which lets the player control Mega Man X instead of Sonic, with all of his signature attacks, like the charge beam, the wall jump and the dash, and X can also get the weapons from his enemies, like in his own games.

Knuckles' Emerald Hunt is a modification of Sonic the Hedgehog 2 that split off from another hack Sonic 2 Adventure Edition. It's main goal is to mimic the Emerald Hunting Gameplay from Sonic Adventure 2/Battle. Playable characters being Knuckles and Tikal, through each stage you must find and collect 3 Emeralds or Emerald pieces. The Game features the radar from SA2, and a secret Sandwich mode in which all the emeralds are replaced with Sub sandwiches and the Master emerald is replaced with a Subway footlong. It also features the Scrapped Hidden Palace Zone and some Sonic 1 Zones

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.

Platform / Puzzle / Sport / Action
Did you enjoy SNOLF: The Sonic Golf Experience? Did you wish you could experience the magic and the mystery of an entirely golf-controlled hedgehog all over again, but this time in Sonic 3 & Knuckles, and perhaps enjoy more characters? Well, feast your eyes on SNOLF 3 & KNOLF: The Sonic Golf Experience, Part II! This romhack, like its predecessor "SNOLF: The Sonic Golf Experience", replaces Sonic's ability to move with a golf-game mechanic, similar to the kind of thing found in games like Kirby's Dream Course. Sonic remains rolled up into a ball under most conditions, and can only be launched when he has come to a stop. The Rings counter instead counts how many shots you have taken, allowing players to compete to get the lowest score!