The main purpose of the game is to defend our routes and bases against waves of giant insects. In order to do it and advance to the next stage, you must build turret defenses in strategic places of the scenario. Each enemies that reaches the other side of the screen or touches our bases without been killed by your defenses causes damage to the shield that is represented by a white bar in inferior part of the side bar, in the right side of the screen. When this shield is depleted the game is over. Each enemy killed by your defenses worth a small amount of money. Use this money to build new towers, to upgrade the existing ones or to repair the shield.