Special addenum: Climbing is painful. First person platforming is bad enough, and it only gets worse when you're put in a dark environment with limited light. Hanging to ledges is not nearly reliable enough for the climbs you expect the player to do, you just fall down when you should be capable of just shimmying over. Plus, it's fine to let the player fall great distances, but you have to consider how they might not be able to get back up. I recommend a much tighter ledge grabbing system that WON'T let go unless the player presses a button, and will try it's hardest to latch on the nearest edge.