A few games I'm looking for are:
Sonic & Knuckles (Genesis)
Super Mario World 2 (SNES)
Sonic the Hedgehog CD (Sega CD)
Streets of Rage 3 (Genesis)
Castlevania Bloodlines (Genesis)
Phantasy Star 2, 3 or 4 (Genesis)
Shining Force 1 or 2 (Genesis)
Some of those games are quite common. If...