The SFX is great! I like the addition of the UFO homing missle concept to keep players moving around. My only criticism is that it feels like the movement has a lot of friction. Though, this could be an intended feeling for the game.
Nice! As the other comments say, love the Cool Math Games style! The movement felt a bit sluggish to me, you may want to consider increasing your rigidboydy's linear drag. Great game!