Lock and Load because its time for a Marine Assault! Resit the oncoming marines trying to infiltrate your base by shooting them down. Upgrade your turrets in order to take them out before your base is destroyed! Build up your armoury to a Heavy Machine Gun, Mortar, Super Heavy Machine Gun, Rocket Launcher, an Artillery.
Mouse to aim and shoot 1,2,3,4,5,6 to change gun R to Reload