I have a problem with the Sega Genesis list. Owning half of the games in your top 20 and 60+ more, there's definitely some titles missing that should be there. No Pulseman? But there's Vectorman? What happened with Earthworm Jim? Not even Earthworm Jim 2? Street Fighter II? But not SUPER Street Fighter II? Why isn't Sonic 3 & Knuckles higher than Sonic 2? Why NBA Jam, but not Tournament Edition?
I guess when you have a list as big as 500, it doesn't matter that one game is higher than another. Only thing that matters is the game was considered.
Personally, I never play Street Fighter II, after I got Super Street Fighter II on genesis. And, I hardly ever play sonic 2 after getting sonic 3 on genesis. I'd owned Sonic 2 for about 10 years before getting sonic 3. I just don't understand it. The big thing being, Sonic 2 had stages removed from the final product. Sonic 3 had those stages put into Sonic & Knuckles to make it complete.
I'd consider things like that, if it were me. But, not just that, I actually enjoy sonic 3 & knuckles more than sonic 2. It was something that got better with each sequel... Until sonic 4....
Then.. Mortal Kombat II... It's really bad on the Genesis. MK1 feels better, and UMK3 is missing animalities, so I wouldn't think it deserves a spot either. It's so much better to have the arcade versions, though.