It has a lot of stuff that I like but I think you might have been trying to do a little too much for the limitation. Switching gears was a bit of a hassle since it turned my car around sometimes while trying to mouse over the new gears. Sometimes it felt like it just changed gears without me doing anything. On the first level, some of the cacti peak out over the tops and bottoms of the walls, make them hittable. I'm pretty sure I won my first race, but I guess I didn't hit all the checkmarks so it said I lost. I'd be nice if there was some feedback to the checkpoints so I knew I'd hit them.
The art was mostly good, but not always consistent. It feels like with a little more time, or with less limitations this could be really cool.