Knuckles' Emerald Hunt
Parent game
Sonic the Hedgehog 2 is a side-scrolling platform game and the sequel to the original Sonic the Hedgehog. Players control Sonic as he traverses larger, faster-paced levels across West Side Island, collecting rings, defeating robot enemies, and pursuing Doctor Robotnik. The game introduces Sonic's sidekick Miles "Tails" Prower, a two-tailed fox who can be controlled by a second player. It also adds the spin dash move, a competitive split-screen multiplayer mode, and pseudo-3D special stages in which players collect rings to earn Chaos Emeralds.
Could be interesting
What if Sonic Triple Trouble had been originally released on the Sega Genesis / MegaDrive, after Sonic 3 & Knuckles?
A multiplayer-only ROM hack of Sonic the Hedgehog. Two players select a character (one being Sonic and the other being Tails) and both battle it out to try to gain as many hits on Eggman. The catch is that Eggman only gets destroyed when the timer runs down to 0 (unless it's a draw at that time, then, it will wait for another hit). The player with the most hits at the end of the timer wins. The player can also win if the other player dies before the timer runs out (if respawn mode is off).
A Sonic fan game set in the SatAM universe.
A fanmade remake of both Sonic the Hedgehog Chaos and Sonic the Hedgehog Triple Trouble for Sega Game Gear, featuring new characters and habilities, new zones and levels, red star rings to unlock new stages, blue spheres special stages, Time Stones, a 16 bit music mode, a hub world, Ultra transformations, a pause menu, a debug mode and cheats, new color palettes and new player camera, gamepad support, 30 and 60 fps support, 4:3, widescreen and ultrawide.
Web browser game based on the special stages of Sonic 3D Blast used for contests on the Sega website.
Sonic Classic 2 is a 2D fangame that is a sequel to Sonic Classic by Hez which will include: Brand New Levels 4 playable characters (Sonic, Tails, Knuckles, and Fang) New unique gimmicks Customizable shields SC1 revamped levels Online Play Extras & More!
Sonic the Hedgehog Classic is a fan game by Hez. It began as an offshoot of his earlier fan game Sonic 1 PC, with a variety of new levels. The game will allow users to play as three characters—Sonic, Tails, and Knuckles—and possibly a custom character of their own. The game features elements from the classic Mega Drive games, as well as new gimmicks. The game currently uses the MMF engine for Windows and has had three releases, with the latest revision (see Downloads) fixing some issues reported by players of the previous version. Moreover, it is Sonic Retro currently being converted to a hack for the Mega Drive by StephenUK. Finally, a few months after releasing the game, Hez Sonic Retro announced that he had started working on its sequel Sonic Classic 2, whose features include various new power-ups and level elements and a complete original soundtrack by Karl Brueggemann.
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.
A truly expansive Mario fangame based on Super Mario 64 that combines elements between it, Super Mario Sunshine, and Super Mario Galaxy. Released in 2009 and featuring 64 Shine Sprites and another 64 Star Coins to collect, it remains the largest-scale Flash-based Mario fangame to this day.
A flash-based Sonic fighting fangame based on Super Smash Bros. franchise. It has some characters from Sonic franchise and a campaign mode.