Atari 2600 - Pac-Man. Some people put this next to ET in level of badness, but I actually got some enjoyment out of it. The ghost flicker didn’t bother me (I mean, they’re GHOSTS after all...)
NES - The Three Stooges, WWF Wrestlemania Challenge
GB - Castlevania The Adventure. Yeah, it’s really slow, but I got used to it. I was able to beat it fairly regularly.
Genesis - Pit Fighter, Super Thunder Blade
PS1 - WWF In Your House
Oh, and for the record, MagMax is actually a lot of fun.