Carve out your own land in the world of Armageddon Earth through strategy, conflict, and labor. Scavenge the land for enough parts and machinery to make a personal war machine for defense or conquest. Raise animals, hire workers, work the land, build a base, and watch as the full ecology of AEO exists whether others are present or not.
Work hard enough and become one of the best artisans around with the best wares for sale. Or, become one of the most feared mercenaries and hire out your crew for missions against others.
Live a peaceful life alone, atop a mountain, far away from civilization. Or, lead a group of dozens, hundreds, or thousands of like-minded people towards the goal of total conquest.