Mainly the A,S,D keys. Might just be a bias from other game that use arrow keys to move but felt it would be more appropriate at Z,X,C or Space bar, not exactly a big deal since you can rebind the keys. I think it would be a good idea to mention the key needed to be pressed for the in level tutorial like the one on 1-1 where you tell the player they can jump but not the key needed to use to jump, since I imagine most players will just jump into playing the game rather than checking the tutorial or settings page first.