Metal Sonic in Sonic 3 & Knuckles is a hack of Sonic the Hedgehog 3 & Knuckles. It was created by Darkon360/GothicReaper/LoneDevil. Metal Sonic is playable, complete with additional special moves.

Hellfire Saga is Sonic 3 & Knuckles hack made with great inspiration from Castlevania and Ghosts n Goblins series by Narcologer.Main Credits:Narcologer - Hack and idea.Programming:Narcologer - Bosses, badniks, HP system, cutscenes, text screens (except very first one), dialogs.TheBlad768 - Source code(modified disassembly of S3K - S.C.E), title screen with disclaimer text screen, credits screen, ending cutscene, bug fix, blood and meat.Sprites:NarcologerModgenTSRMusic ports:TheBlad768Sounds:NarcologerTheBlad768Level design:NarcologerBeta testing:TheBlad768FireratMr. CatFoxConEdStoryline:NarcologerExternal Credits:ValleyBell - midi driver, mid2smps, vgm2mid, wtmd2mid, smpsconv.Flamewing - smps2asm.Clownacy - Sonic 2 Clone Driver v2 (v2.7+ prototype).

Super Sonic in Sonic 3D is a hack of Sonic 3D: Flickies' Island made by Sik. This hack allows the player to turn into Super Sonic in said game after collecting all sevenChaos Emeralds, mimicking its prequels Sonic 2, Sonic 3 and Sonic & Knuckles. The rules are borrowed from the latter two games, so the player must double jump to transform and also must not have a shield in that moment, besides the basic requirements (having all emeralds and 50 rings).All of Super Sonic's behaviour is implemented: a custom palette, a transformation pose with a fading palette, invincibility (with stars), speed shoes and a music change upon transformation. Rings drain while transformed as well. Super Sonic can still be killed by getting crushed by some falling platforms, however, so he isn't completely immune to death.This hack is based off Sonic 3D: No Flickies, and as such it shares the same gameplay rules.