The game is fun, though. It's like a vehicle based Monkey Ball, really. Each level has 3 objectives too (you aren't expected to get them in one run, though). You can collect all of the stars (think banannas in SMB), grab the GS emblem, and finish it within set times.
While you are using a vehicle, it hardly adheres to any realistic physics. The game allows a crazy amount of air control like some sort of vehicle based semi-platformer or something. You can even use the sixaxis motion sensing function to adjust your car in mid-air.
The game takes a while to get into, however, due to the unique handling and the tutorial levels are really small and simplistic.