Hellforge has whipped up a two-page article that briefly analyzes the post-apocalyptic settings utilized in a handful of video games, including Fallout 3 and Diablo III.
Barter and trade exists, with bottlecaps and bullets the main forms of currency. Bottlecaps, huh? I guess recycling was a bad idea after all. It's a strange world frightening, even. I mean, bottlecaps? Come on. But seriously, radiation has taken its toll on the environment, causing horrific mutations in humans, and turning wildlife into feral monstrosities all in tune with a 1950s pop-culture view of science. Yeah, people believed in some crazy stuff back then, and the whole idea was that when you get hit by a dose of gamma radiation, you turn into the Hulk or something. That's the kind of crazy thing that defines the world of Fallout, and that's what sets it apart from every other (bombs fell, everything died) scenario out there.
Set in the aftermath of the previous game, the world lies in ruins, due to the destruction wrought by the forces of hell. Twenty years have past, and most people can barely remember the events that culminated in the destruction of the Worldstone, and those who do, do not wish to reminisce. Yeah, I guess people are pretty forgetful like that, and who could blame them for not wanting to think about how some nasty little goblin jumped on their dad's head to rip it clean off? I mean, you could only imagine what these people have been through, so can you fault them for wanting to just get on with their lives?