When Sonic & Knuckles was released, it boasted the ability to be locked on to other Genesis cartridges and have something special happen. Unfortunately this really only applied to Sonic 1, 2, and 3. Upon locking onto Sonic 3, you could play as Knuckles in Sonic 3, among other things. Locking onto Sonic 2 allows playing Knuckles in all of Sonic 2. Now, locking it onto Sonic 1 would make you think that it would let you play as Knuckles in Sonic 1, right? Wrong. Due to limitations in the Genesis, Knuckles red palette messed up some of the other spites within the game. So instead of this we were treated to this "No Way? No Way!" screen (Called Blue Sphere in Sonic Mega Collection) which lets you play a SHITLOAD of the Sonic 3 Special stages. So, no Knuckles in Sonic 1, right? WRONG. Megahacker Stealth created a port of Knuckles in Sonic 1, complete with gliding and spindashing. To prevent the palette issues Sega experienced, Stealth modified Knuckles' colors to something that had minimal interference to the rest of the game.
DOWNLOAD THE HACK HERE
Now for added effect, OrdosAlpha modified Stealth's hack to fix Knuckles' palette, and made any sprites that got messed up look better, as some of the below screenshots show.
DOWNLOAD THE ALTERNATE HACK HERE