In each level you need to get from point A to point B as quickly as possible. You also need to get all of the stars that you can in order to get a better score at the end of the level. Try to take down as many enemies as you can along the way. However make your focus about getting to the end of the level, enduring as little damage as possible, and collecting all three stars. Not recommended for play with out a mouse. The keypad on a lap top is more difficult to control and you need it to fire your weapon.