Wait for the game to load, then click on the game screen with your mouse to start. 

Use your left and right arrow keys to move your ship left or right and use the spacebar to fire.  Shoot the Spacey Invaders while avoiding their missiles. 

You can hide behind your buildings, but they probably won't be there for long!  Shoot the UFO's for an extra bonus. 

Remember, Spacey Invaders move faster as they get closer to you, so be careful and good luck!