What they had was a couple pieces of wood (later plastic) with precise marks on them, with one of the pieces moving up and down against the other one.
This device was called a "slide rule" and it was good enough to do the calculations that got us to the moon.
Subsequent games are set successive decades after the first, with the world continuing to evolve with new factions and adventures.
The original just follow the critical path to the ending, but you'll barely scratch the surface of what the games have to offer.
Along the way you'll meet mutants (humanoid and animal alike), raiders, robots, cyborgs, tribals, cannibals, and more.Of course, something existing doesn't necessarily imply that it was common enough to just show up in the chronological and spatial span of the work or at the frequency it does in the work, which is why period pieces in which all the costumes are reconstructions or composites of documented outfits still manage to be fashionable for the period the works are written/produced in.