I've got an idea for a new level set:
You could make Levels (or Levelsets)
with graphics of different ages.
(futur, prehistory, middle ages, the wild 80s etc...)
I'm creating a n alike level this time, but
I don't believe that it's zeitgeisty...

But maybe you can do that better than me, maybe
you have more experience with graphics and graphic design.
Sascha