Grey Wars - alien forces are attempting to steal cows from our barns, and it's your job to stop them. Build a variety of turrets to destroy the invaders. Research new technologies to improve your military capabilities. Click on turrets to upgrade or sell. Click on turret in build area or press 0-9, - to select a turret to build. Space to select an air strike. Hold W while clicking to quick upgrade. Hold R while clicking to replace. Hold S while clicking to sell. Press T go deselect turret.