Interesting concept. The art is pretty cool, the audio feels good too. I think my biggest complaint is how hard it is to make turns with how slide-y the vehicles are and turns not being seen from far enough. I liked the idea of racing with different vehicles that was cool. However, I didn't feel the 3 races offered much of a variety, it felt like I am just going through the same race using a cosmetically different vehicle but everything the same. For example, in the helicopter race I thought the entire map would be opened up as a "show me what you got" for example with minor obstacles in the air. Or in the boat race how now there would be different waterways (which is partially implemented).
Overall, interesting game. I can see this becoming quite a bit of fun if given enough time to grow as an idea.
Good work!