In this game hostile aliens attack Earth. You must protect it from the invaders. You have a cannon on top of a tower. When enemy ships approach you must shoot them with this cannon.
How to play?
Controls: Use your mouse to shoot. Press A-D or the arrows to move the screen. Watch the power bar. You can't shoot if you're out of power. The power recovers automatically when you stop shooting. Shop for numerous upgrades between levels.