Aliens are invading the Earth, and it's up to you to defend our home. Stay alive as long as possible by defending the Earth from the invading aliens.
Destroy an alien or comet by, tapping on them with your finger(s), by activating nukes earned throughout the game, or by allowing them to crash into each other. The more aliens and comets you've destroyed, the faster the aliens and comets attack.
Try to get as high of a score as you can! Every alien you destroy, your score increases by 1. The game is over when an alien or comet hits the Earth.