You have to accomplish missions, that essentially consist in capturing target cars, that are signaled with red circles. You have to hit them until they are destroyed, but avoid collisions with the others or the damage will destroy yourself! To pass to the next level you have to earn certain amount of points. Many bonus and power-ups are essential to progress: health, speed, wings and jump.
Arrow keys to move, space bar to use the bonus you have (speed, wings, jump).