I think the handling needs a bit work since i always collide with the sides (i think it needs a bit more force when turning left/right). Also the physics seem to be affected by the framerate - i get wobbling at 25 fps, stuck at 300+ fps (when i run the windows version) and weirdly enough it feels most responsive and stable at 9 fps (running in high resolution) :-P.
Graphically it is impressive and i really like the music. I think it needs a bit more on the gameplay side though - even if it was something as simple as obstacle avoidance (with the appropriate widening of the track). I'd like to see more levels or perhaps a random track generator?