Confession time: I've only played through most of those Genesis games once apiece, and never went through GH a second time. That said it's rightfully regarded as a cult classic.
It was praised as 1993's game of the year by GameFan magazine who subsequently became obsessed beyond belief with Treasure to the point of even offering glowing reviews to their next project.....a Ronald McDonald action-platform game. I am NOT making this up. They went on to do Dynamite Headdy which I started playing and then just sort of forgot to finish, and the N64 game Mischief Makers, which I didn't get past the second level of, back during the big N64 game-drought. (Treasure apparently never made any SNES games because of that aforementioned slow SNES processor, something that I read in a GF interview back in the day--and don't forget what a miserably uncool company Nintendo was back then!)
I forgot an SNES game I pirated: Sparkster, the SNES version of Konami's Rocket Knight Adventures, perhaps Konami's attempt at making their own Sonic type character (if you've forgotten, it's an opossum with a jetpack and a sword.) In retrospect, that's not a particularly great game.