To start the true end game section, complete a Wormhole Digger defense in the Base Camp. Start the digger and begin defending. You can then assign soldiers to Base Defense. During Base Defense, try to stay until you earn an "S" rank to get the best possible rewards, including a Machine Gun Turret recipe. The blue turret is an AI-controlled machine gun that automatically shoots enemies that get close, making it one of the most valuable weapons for future Base Defenses.