The goal of the game is to protect your software from harmful threats: adware, spyware, viruses, etc.
To kill security invaders you must build security shields on the game desktop. All invaders, except viruses, can’t go through the shields.
Instrucciones del Juego
You must place shields on the desktop to change movement direction of the invaders and to force them to pass longer way, to give your shields time for destroying threats.