Ok, this is controversial.
It's not a post-apocalyptic setting, and I haven't even finished Fallout 1, but to me so far at least the mood is exactly the same:
Once upon a time in the west.
While this is more about the building of a new civilization and not so much about adapting to the fall of civilization, both are points of transitions between the old and new and share a same status quo. Of course they also share common elements, like the dessert, gunslingers, technology that doesn't work anymore/yet, etc.
And on top, it's a very good movie, even if you don't agree that it fits the mood.
DOES anyone agree?