Not that good
The thing I did not like about this was that it just didn't seem to have much dimension to it. There are so many better flash games out there, it's hard to recommend this. I think the best thing for you to do is put more detail in. Shading is always important for a well detailed game. This just didn't seem to have much going for it. I did think this had its good points, because it did have some good effects.
The sound wasn't that bad, but it wasn't that good. I guess next time you should just try to have more detail in it. The backgrounds are pretty bad, but at least the car itself isn't terrible. I found it weird how you called it a car when it is clearly a bike. Well, I'm probably just overanalyzing something that probably isn't meant to be analyzed like that.