Penumbra (video game series)/Nightmare Fuel

Where to... even... begin... Most examples here will overlap a lot with Fridge Horror and Primal Fear.

• The fact that in Overture several people were unable to get out of the mine before everyone else left, forcing them to stay underground, mostly in complete darkness.
• The sight of the man at the end of the hallway, seemingly missing an arm is enough to make someone jump out of their seat, but the combined fact that the lights slowly go out, and then your flashlight stops working, does nothing against the surprise of when a seemingly locked door ends up killing you.
• One of the early notes, written by the Spider Hater, recalling how he woke up with a large spider nesting in his mouth. And swallowed it. Not to mention the journal page where he recalls having to amputate his own tongue - without sedatives. You can also pick it up and play with it.
• Red was trapped, alone, in a hellish nightmare, where he could eat only slugs, for thirty years, and he couldn't even kill himself. That in itself is not the true tear jerker. Red was trapped down in that mine, at the age of 14. Imagine yourself as 14, now imagine being torn away from everyone you ever knew, and experiencing what he went through. No wonder he went mad.
• The nightmares Philip has when Clarence merges with his mind are beyond horrifying. Philip wakes up after being chased through the final room by the rock worm.
• The monsters you face through BOTH games are Nightmare Fuel incarnate. Dogs, Giant Spiders, GIANT rock worms, The infected lab staff. Whooooa nelly. The things the Infected say when they find you... "YoU ARe DeaD!", "TheRe Is NO PoINt In HiDInG!", "WhO ARe yOu!?", "YoU'D DO BetTEr StAYiNg PUt..." eep.
• The writing on the wall in Red's room.
  • LET ME DIE PLEASE!!!!, Whats beyond, Red is dead, Get out of my head, Nobody to TALK to, DEATH, Poor lady
  • Well, "Red is dead" does provide a bit of Nightmare Retardant for those who have seen the French comedy La Cité de la Peur...