From the developer's website:
"Take command of your mercenary forces in Atom Zombie Smasher. The zombie apocalypse is upon us and it's up to you to evacuate everyone before they fall prey to the undead.
Conduct massive rescue operations with a helping hand from snipers, artillery crews, orbital bombardments, and more. Experience the tactical richness of fully-destructible environments and procedurally-generated campaigns. And when the apocalypse ends, create your own game mods and share them with the Online File Share."