The sensitivity is not defaulted to zero and that never happend to me in any build...? so maybe just reinstall the game? Else I don't know what the issue could be zombies spawn at the doors(which are also behind the player) which I feel like makes sense. Yes there is a setting for fov. Just hit Escape go into options and change it with the slider beneth the deafult text "Fov: 60"(this will change acording to you fov so you can tell what fov your playing at). Thank you for the feedback!