It's the lack of variety that does it for me. While I actually don't hate the original SMB game, the physics are quite off, making Mario's jumps unwieldy and harder to control. Especially mid-air course corrections or the lack thereof. And a LOT of the Lost Levels' challenges are jumping related. It's not a horrible game, but I don't think anyone would appreciate it if it wasn't for some imaginary insulting controversy. It was a nice what if back in the late 80's, sure.And yeah, the theory of it being too hard for Americans just doesn't hold water for me, either. If they had such an issue with that, why not just tone down the difficulty instead of not releasing it stateside?
Continuing with game sequels, while I do agree that Ms. Pac-Man is the better follow up to Pac-Man, I have a soft spot for the unloved sequel, Super Pac-Man. Not only was his character one of the best things about the 1980's cartoon series (too bad he was only on second season), but the game is quite a bit of fun that manages to be the same and different. Not to mention how funny it is to run by ghosts as Super- Pac-Man, and have them distorted with fear.