Nobody was ready when they came. The invasion took the world. Stop them. Use WASD to move, mouse to shoot, space to change weapon, G to throw grenade. While you will progress in game story, you will get additional items to build, three type of traps. You can use them by clicking on the icons. You can change weapon by clicking on grey icon, do not forget to check your ammo supplies. Kill monsters, explode bases and find survivors.