Global Defense System
Global Defense System - a good castle defense game. Your objective is to save the world from a wave of asteroids that are heading straight towards earth! Upgrade and buy weapons platforms between levels. Every weapons platform has the capacity to hold up to 2 types of ammo. Keys Q/W/E select secondary ammo while keys A/S/D select main ammo for platforms 1/2/3. Earn cash by destroying asteroids. Automated turrets can be purchased. Turrets require visibility in order to function well. You can increase visibility between levels.