Fortress Protector

The goal is to protect the fortress of the enemy invasion and get the best score possible. At first you have 2 turrets available, one is a machine gun, the other a mortar. When you touch and slide your finger on a turret to your target, it turns on and fires continuously until you give it a new order. Randomly, a killed enemy drops a item of energy that can be used to recharge the battery from the laser turret. When the battery is loaded, a sound will warn you that it is operational.