Team up and shoot down waves of invading aliens. A top-secret government laboratory experiment went wrong, and now invading aliens have infested the military base. Time to clean things up! Grab your weapon, recruit a friend, and start blasting wave after wave of alien scum into oblivion. Obtain more powerful weapons, battle against enemies of all sizes, clear each room, and restore order to the facility. Play a single player or co-op multiplayer campaign, and have a blast. Features Survival mode Boss Rush mode Top-down shooter gameplay Single player or co-op multiplayer campaigns Multiple weapons and enemies Multiple difficulty settings