Wolfenstein: The Old Blood

Here is my (Walk) Playthrough for the nightmare boss level. First of all, the Location of the Boss Level is after you passing the electric door (unmissable). Go left Side two times and you see a Hole, fall down and at the next Wall left side is a very small gap, use it and here you will find the Bed aka Nightmare Boss Level. The level itself its one Room with the Boss, nothing more. On easy or Normal the Boss is no problem (you dont have play the Nightmare level on hard or Uber)

Very easy boss fight, it is harder to find the mattress to sleep on than the level actually takes. In the last chapter you will go down an elevator and have to proceed to a tunnel, there will be enemies, now at the end turn left and there is a door, shut it down and pry it open, now go left and you are looking for a very small gap to fall through, once you have found it sleep. The boss is super easy, go through the door and on the left of the room there is a secret quite far up, in the secret is a MG42, use this and the moss drops with only a few bullets.

I did this playthrough on Easy just to show you the final level. The boss drops with just your normal machine gun.