Nuclear war, zombie outbreaks, meteor strikes, economic collapse, alien invasion, no matter how it happens an apocalypse makes for a unique and engaging setting to run a campaign in, even for a jaded GM.
Here’s a few quick tips that can make a good zombie or other post apocalypse game a great one, and keep the group coming back (from the dead?) for more.
A small band of squirrels seems to be fighting high up in a tree over a shiny nut-sized object. Can you retrieve the prize without scaring the squirrels into running off with it? If they do, can you manage to chase them down?