Overbound Game Studios

Sonic Time Twisted is an open-source Classic Sonic style fan-made game, headed by Overbound. The game tries to improve upon the best features from Sonic the Hedgehog CD and the other Genesis/Mega Drive games. These features including time travel, elemental shields, and 3D special stages. The player controls Sonic and co. and they play like they do in the Genesis titles. Like in Sonic the Hedgehog CD, the player must use time poles (now adjusted to be instant) to travel through two different time zones, Past and Future. In the Past, Sonic must find the Special Stages and collect the Time Stones, while in the Future, Sonic must also find the Special Stages, however, these have the Chaos Emeralds. Beat all 14 Special Stages in each time zone (7 each) and the player will achieve the True Ending. Besides that, the player must traverse through 8 zones, most with 2 acts each, reach the Goal Post at the end, as well as encounter a boss at the end of the stage be it Metal Sonic or one of many loyal Super Badniks.

Spanner

Sonic 2 Dimps Edition is a hack of Sonic the Hedgehog 2 by Spanner. This hack attempts to mimic what Sonic 2 may have been like if it were created by Dimps. This means incorporating many features found in Dimps games such as random speed boosters. This does not include features common in most modern Sonic titles with the exception of a homing attack.

ZykovEddy

Sonic the Hedgehog 3D is a free fan game about a famous SEGA mascot, Sonic, and it is made on Build Engine with additional EDuke 32 port. The game was inspired by two classic Sonic series: Mega Drive/Genesis and Sonic Adventure series.

DNXDelta, Thorn

Sonic 2 Retro Remix is a large-scale ROM hack of Sonic the Hedgehog 2 for the Sega Mega Drive, created by Thorn and DNXDelta. The goal of the project is to create a 2D Sonic the Hedgehog game that requires exploration to progress, as well as the requisite platforming and sheer speed. A mission system akin to those of the 3D Super Mario games is implemented as the means of progressing from one level to the next. Missions involve earning Chaos Emeralds in scavenger hunts, boss battles, speed runs and score attacks; most require learning each level's ins and outs, instead of just finding the easiest way to the goal.

TheBlox

Tails' Nightmare 2 is the sequel to the Sonic the Hedgehog fangame Tails' Nightmare released for browsers on 16th November 2010. Like its predecessor, the game is loosely based off the Tails Doll creepypasta. They contains improvements, Wall jumping and rail grinding are two new features added, and the gameplay itself is much smoother than the last and a variety of difficulty setting options.

GalaxySoftware

Sparks, MCKaosu, Gamenerd Advance, LarkSS

Anton Huckleberry

Headcannon

Funstar Entertainment

Cinossu

Sonic the Hedgehog 1 @ SAGE 2010 is a specialized ROM hack of the original 1991 game for the Sega Genesis, developed by Cinossu. It was released specifically for the 2010 Sonic Amateur Games Expo (SAGE).

No More Blue

Comet Games

LSF Games