I like this entry. The music really enhances the unusual atmosphere.
I played it a few times, but unfortunately one of those times I hit a car and popped out of the tunnel, falling forever. It was kind of interesting though as I could see how you'd constructed the level.
A small thing, but using LMB to trigger the 'powerup' seemed like a strange choice. I think a key press, like spacebar, could feel nicer.