This will hopefully be useful, especially for TDM newcomers (it doesn't happen very often but can still catch me out sometimes): Most successful jumping depends on you standing up when you make the jump. Unfortunately, sometimes the crouch indicator will indicate that you're standing up when you're actually stuck under something that's keeping you stuck in crouch position. To check whether this is the case, toggle the crouch key - if your viewpoint doesn't rise and fall, you're underneath something (a window ledge, joist, rock, whatever) that's stopping you from standing up. The answer is to put yourself in standing position, then edge out (away from the wall, usually) until your viewpoint raises. You are now standing and can plummet your death anyway make that jump! Thought I'd mention it as there's one particular climb in Requiem that I had this problem with, and others seem to be too: -