A powerful alien space station is about to launch as missle that will destroy the Earth. You are piloting a small spaceship armed with laser guns and bombs. YOUR Mission; Destroy the space station and save the Earth!

Quickly bomb 8 alien missile silos.  Shoot as many alien spaceships as you can.  You must hit all 8 silos before "Planet Earth" moves directly over the Launch Trench.  The Trench is guarded by alien saucers and meteor-missiles which attempt to destroy your ship or distract you from your bombing.  If the Earth gets into attack range (center of screen) before all silos are destroyed, the next silo to appear on the screen launches a missile which destroys the Earth!