Hey dropp. Thanks for your kind words.

For the tracks, we actually use two kinds of walls. The visible one which you can see with your eye and an invisible one, where you actually collide to. This way we can manipulate values of energy and speed taken only when colliding with a wall and even detecting how strong the impact was.
But for further questions about that subject you better ask/wait for zero3growlithe's answer since he is our coder and he set it all up. Meanwhile, enjoy the trial! Maybe you can share a gameplay video with us? We like to see how people are doing on the tracks