Upside Down shooter

For my upside down shooter i have came up with the idea that you are in a farmhouse and out of no where you start to get attacked for zombies. You will not be able to go outside of the farmhouse and have to survive until sunrise. The Farmhouse will have various openings so that the zombies could enter the house and kill you, but each entrance has a barrier e.g window (you will be able to fix these barriers in game)

Your starting weapon will be a pistol, but you will be able to upgrade your weapons to > shotgun > machine gun > flamethrower > rocket launcher > minigun (prices of these vary ,lowest being shotgun ,highest being the minigun)

You will also be able to upgrade your barriers as well from window > mesh > wood > metal > metal + barbed wire (prices of these vary ,lowest being mesh ,highest being metal + barbed wire)

You will also be able to build towers as well to help you survive these will be machine gun > Flamethrower > Cannon > Gatling gun > plasma (prices of these vary ,lowest being Machine Gun ,highest being Plasma)