This game is great fun, the physics aren't totally realistic, but for a ten buck title what do you expect?
There are a range of vehicles to chose from (the stunt planes are impossible to fly!) and I've had loads of fun in multiplay mode on the tiny 50cc bikes.
there is even a national competition mode which allows you to compete throughout a season, and unlock new bikes/parts/helmets/clothing.
This game is not hardware heavy, and would be a fine title for kids to play with.
Learning to master stunts keeps the game interesting, and the track editor (although complicated to get the hang of) gives you great freedom to ride/drive the tracks YOU want.
I'm giving this an 8/10, based on fun, and playability by any machine, spend your ten bucks on it RIGHT NOW!