Kill the UFOs!

1. Use the arrow keys to move the spaceship and the space bar to shoot.
2. The aliens have magic powers that let them teleport between ends of the screen - you don't! But you have better guns and the aliens are stupid and can't aim.
3. The gold balls give you extra points and the hearts give you extra lives.
4. Be careful when the boss comes out! It shoots more aliens!
5. You win if you figure out how to destroy the boss.