War of Worlds is an amazingly simple and quite addictive action style game.  Just go out and defend your city from the alien ships - shoot at them and get more and more points. Be careful not to hit the Earth ships - they are on your side and if you destroy one of them you'll receive negative penalty points. It will be good to shoot at the asteroids as well for they may give you a bonus. So - what are you waiting for - go out and show them all what you can do...