In this 1st person shooter, you are in command of a Laser-Cannon Platform and you must defend your city from alien invaders attempting to destroy it.
Controlling your sights, you must move about the city, scrolling left or right, in search of the invaders.
Once you find one you must blast it before any damage is inflicted to the buildings or yourself.
As you fire you must be careful as you can also destroy buildings as well.
Your Laser-cannon can take five hits before it is destroyed and it is game over.
Before the game you can choose a skill level from moderate, difficult or impossible.