Attack of the Zombie Nuns

The game idea that i have been thinking of is called "Attack of the Zombie Nuns" which would be a first person shouter(FPS). The role of the gamer is to navigate their way through the vatican exterminating the zombie nuns that have taken over,the users end goal is to blow up the vatican from the centre to contain the zombie infection. The user will be armed with a small arsenal of weapons including handguns, machine guns, knifes and explosives to name a few. The screen will have the standard information for a FPS, this being a health bar, an ammo bar, and a compass to direct the player in the right direction.