La-Mulana/Nightmare Fuel

• The sacrificial pit of Shu in the Confusion Gate, where a seemingly endless line of virgins fall down a tall pit to their death on the spikes below. Their blood is dripped onto the miniboss Shu, who regenerates HP whenever a drop of blood drips onto him. Somehow, the corny 8-bit graphics do not make this any less shocking and disturbing, and the creepy music (which by now has been drilling itself into your head for an hour or more) doesn't help matters, either.
• The Confusion Gate is filled with large head-statues which look entirely too happy. The aforementioned sacrificial pit has several of them.
• The Mother's third form, a giant, pale-faced version of the Virgin Mary who rains crosses and tears of blood that explode into walls of flame. Also, it's holding a skeletal baby.
• The background in the Temple of the Moonlight has demonic faces woven into walls made out of red vines or tentacles.
• Tiamat. She has a very creepy distorted facial expression when doing a certain attack and another one after losing a certain amount of health, and if she kills you, this Slasher Smile tends to be the last thing you see before the Game Over screen...