A Good Start
I'll start by saying that the graphics are very nice, all of the ships look decent, as well as the backgrounds. The pilots look a little strange though. Now for the critisims, the ships all look different, but the handlings seem almost identical and I could not easily tell exactly what was different about them except for their appearance and size. The race tracks were very bland and boring, granted it is a demo, but there was nothing interesting about the tracks themselves. A suggestion I might make would be to insert boosters, objects in the way, something to actually require some skill or reflex. I was pretty bored while driving the things, I'm not sure how you are imagining they are propelled, but I might suggest some kind of sound effect to go with the driving, and a glowing at the back to suggest a jet? The speed could be increased to make the game more engaging and intense as well.