Your mission in this remake of ATARI multiplayer classic is to defend your base against an alien missile invasion. Use YOUR MOUSE to aim and click LEFT MOUSE BUTTON where you want your rocket to explode. Roll over the green energy points to collect them. If you have enough energy you can buy upgrades from the top of the game screen. And don't fire to fast. If you are too fast you might run out of the missiles and wait for them to reload. Good luck!