The original Dragon’s Lair is a laserdisc game published by Cinematronics in 1983. A “port” for the Genesis / Mega Drive was in development, along with the SNES one, but it was never released. Dragon’s Lair Genesis / Mega Drive ROM leaked sometime around June / July 2011, it’s almost bug free and more or less complete. It is a port of the released SNES version. You can find the leaked Genesis / Megadrive version in here.
Video from Segadatabase: