I can see what you were going for here, there is always room in the world for a clever FPS with a twist, but it was really tough to digest this one for one reason, it was just too dark.  Darkness is a great premise in a game but there needs to be some way to navigate the game through the darkness beyond simply wandering around hoping to find something.  Good effort, I know that doing a 5 day Game Jam using the Unreal Engine is a real challenge.