Eliminate all the enemy insects shooting at them with the spacebar. At the end of each level you will find a huge insect waiting for you. Move with the arrows.
Eliminate all the aliens. Move your submarine with the mouse. Gather the batteries to score points and improve your weapons. Make click to throw bombs. The submarine can't shoot automatically.
Destroy all the robots and face the final boss from each level. Use the arrow keys to move. Hit with your baseball bat pressing the space bar. Activate your special attacks with A,S,D and F.