this game is top-notch if it comes to this genre. i really liked it a lot. (and i actually hate these kind of games). it was pretty easy though.
but there is one thing that's not good; you only see one checkpoint when you're driving, and you don't see where you have to go next, so this gives you a disadvantage at maps like the rally maps blocks and blocks 2.
so i would recommend making 2 checkpoints visible, the other one at a different color/size, of course. the rest of the game was nearly-perfect! keep it up. :D