I think your missing one.
"Cheap" level design.
The kind where you could have infinite godlike reflexes, but still die the first time you play.
For example, a square that looks like every other square kills you instantly.
Or another example, though one supposed to be that way in I want to be the guy where the apple falls upwards.
I'd even consider putting Quick Man's stage in MM2 their, because depending on how you fall your screwed. (unless you use flash anyway.) I probably wouldn't however since the default dropdown gets you in position... and it's if your tricky with it that screws you up.