So...in the background of the ice age I see massive "dinosaur" skeletons. But people are alive in the ice age. I'm really hoping this means that some of the "raiding parties"/bosses are screen-filling carnivores that you have to jump inside of to destroy.
Procedurally-generated intestines with amoeba sub-bosses and a heart that you have to find and kill to stop the creature from destroying your settlement would be...ummm....AWESOME.
Edit: Not much correlation between my first 2 sentences, now that I re-read them. So, to correlate - apocalypse + different time periods + dino skeletons in one of the "future" time periods = (hopefully) massive monster/boss/levels in the "past"