This is a game about sustainable energy use and blowing the crap out of mutant alien zombies.

During the day, you will build up your base and manage your resources in a post-apocalyptic world where oil and natural gas become ever more scarce. Research alternative energy sources and upgrade existing facilities to get enough energy to survive.

Then, during the night, use the energy you produced and conserved during the day to fight off hordes of mutant zombies.