That's cool. It seems like a solid game, and i like the level. The intro and menu were pretty slick too, although you might to hide the mouse in the former. What i would work on is firstly the control of the ship. For a hovercraft it seemed very jerky. I think a bit more momentum ,so that it takes longer to get up to top speed, and you need more skill to drift around corners would improve it immensely.
Also, i think a mode where you have to race to collect the gems around a linear route would be more enjoyable- at the moment you have to "scope out" the whole level first to find what route to take. For me this seems a bit daunting- i would prefer the way to take to be obvious, and the game and the fun be derived from skillfully navigating the course- ie your driving.
BTW, how did you make the levels?
Another thing is that on my comp the program after being clicked (from windows) appeared to do nothing for of order 10 seconds. Maybe you should get it to flash up a "loading" screen in the meantime.
You'll be able to click on this someday.