Let's see. You should be in Level IV. If I remember right, that should be the first the level with a switch. You're supposed to hit the floating symbol with Attack. I should probably put the symbol on ground level rather than having to have the player jump to hit it. You turn the level to Night which should solidify the moon box allowing you to wall jump and return you to Level III. R returns you to the last door you entered through which should be the door above the moon box. You could only return to whence you came at Night.
Hmm. You know, that might be a good idea. Cancelling vertical movement only when pressing against the wall. Though, that might still interfere with horizontal movement post-jump.