Your objective is to finish each level with the highest score you can get by performing stunts and acrobatics in mid-air without crashing and dying. You can choose to play through 40 levels or play an infinite level to see how far you can go without dying. On each level, you will see purple gems that you can collect. These are the currency you can use to unlock and buy one of the 8 different available bike models. You can earn up to a maximum of three stars at the end of each level depending on your time score.