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.
Most large mammals, such as elephants, rhinos, and their modern ilk are ill-suited for domestication, but that doesnt exclude their use as engines of war. Rather than raise and train the Mammoth from birth, Mammoth Handlers instead capture the wild Mammoths at a young to juvenile age and train them for war. These animals are draped in armor and are unleashed as living war machines against the foes of the Mammoth Tribe.