I've been currently working on a zombie game where zombie's will attack your house. So far I'm able to scan the room place a window on the wall and have zombie's start walking towards the player and attacking them. I know it's a long shot from having a fully developed FPS but why not? these zombies are harmless. I'm currently working on masking the plane and making a collider for the zombies to enter through the Window. I'll write a tutorial on how to break glass later ;-)
hope you enjoy the video if you have any questions you can contact me here.