We felt that zombies would be a great fit for our apocalyptic-city setting, but not as people brought back from the dead. Rather they are citizens who were either infected with some sort of virus, or who fell victim to the side-effects of rapid mutation. They roam the streets in seemingly mindless packs... until they find prey to fixate upon. It does not look like they actually hunt to eat either, but rather just attack for fun.
The name "Zombo" arose as a working name that sort of stuck in an endearing manner. But if you can think of something better we're all ears. Let us know what you think of the design and what the name should be in the comments!