Really fun game, but i think $10 would be a better price IMO.
this is the kinda of game which hooks you in and you play for hours each day, but then hit a ceiling (either of skill or frustration) and then burnout and never pick it back up.
overlaying your friends best times on the track (for both normal levels and skill games) was a great touch. i found myself playing longer just so i could beat their score.