It's pretty good; could use some medals and there's a fairly hefty bug right at the end of the last level. If you overshoot the ending by going too high (say by boosting), you end up going miles over the line and falling into a pit, where you get 'caught'. Trouble is, then it comes up and says that you managed to go 129% and would you like to try again? Not really. Otherwise, great game. I have a real soft spot for these upgrade mechanic games!