This is really impressive. I can really picture this doing well. My complaint is that holding the button down can occassionaly go wrong, you can easily go too far or not far enough, which can be more frustrating with the slow animation when restarting. I get that you can't be able to move the same direction twice. I think, it should be that, when you change direction, you can't move the previous direction but you can keep tapping in one direction until you change, if that makes sense.
But seriously, great job!