Hey, I loved the mechanic of the game! I played each level for about 5 min. I know 15min is not a long time but here are my thoughts.
My favorite level was the middle one where the roads crossed. I would just wait in the middle and try to hit the cars as they passed by. I was able to get really far that way over 7 laps. The other tracks where much harder to hit other cars with. My favorite part of the game was the switching of cars and I think the roads crossing made that happen more often.
The camera being slightly out of sink with the character made the game really hard to get used to. I think this made the driving more difficult then other racing games I have played.
Great Game!