I thought it was a fun game. "P" to restart the game wasn't explained anywhere though and I got a bit confused about what is meant to happen when I come to a standstill. A total distance travelled marker would be nice too but the course was great.
P is sort of a secret key. The R key is used for resetting the car to the last checkpoint. So you found a secret. If the car comes to a standstill you have failed and must reset. I think I need to find a way to prevent this as much as possible.