Your goal in this ultimate defense game is to take control of 4 separate turrets as you fight off 30 waves of enemies. You earn cash for destroying the enemies. You can use your money to upgrade your turret and buy new weapons (you will have to buy weapons in the scenario mode to use them in survival). You can save your progress after each wave. Use YOUR MOUSE to aim and LEFT MOUSE BUTTON to fire. Use 1-6 KEYS to switch weapons. Press "W", "E", "R" KEYS to turn on/off secondary cannons. Hit "T" KEY to turn off all secondary cannons. Press "D" KEY to detonate nuclear mine. And use SPACEBAR for laser targeting. Good luck! Multiple Power/Armor and Weapon upgrades as well.