GTA: Zombie Wrangler
The Zombie Apocalypse is here and everyone knows that it would be dangerous to live alone, but you don't have a choice since the others are searching for food. You are left all alone to defend the base against the zombies. In this game, you need to defend the base till your allies get there. You start with a simple magnum, but you would make money from killing zombies and you can use it to buy better guns. You can also upgrade your existing gun. If you want, you may get a better fence. The game would be harder, so you need all of that.