A cluster of asteroids is approaching and threatens to destroy Earth. You're the pilot of a spaceship and your objective is to fire at all of the asteroids as they approach. Use your weapons skilfully and hit them before they damage your ship.
Use the mouse to select the difficulty level of the game; use the arrow keys to move; press the spacebar to fire. If you destroy them, your score will increase. Press 'Ctrl' to activate your shields. Don't hit the asteroids or your ship will be destroyed. You have 3 lives. If you survive for 30 seconds, you'll move on to the next level.