I'm not really an expert here, but I'm going to point out the biggest problem I noticed: your collision is WAY off. Like Darren said before, if you hold against a wall long enough, you'll go through it (and what's the point of having walls if you can just go through them, am I right?), making the levels too easy. The fact that it's only got three levels doesn't really help either, as you could get through this game in a matter of thirty seconds if you have issues going through the walls. That being said, I liked the concept. Clean up the gameplay, fix the collision detection with the walls, maybe add some more levels, and I think you'll have something that people would love for its somewhat unique presentation.