Rule of Rose/Nightmare Fuel

This whole game fits this trope once the player fully understands what's going on.
"The Unlucky Clover Field" chapter shows Martha being beaten and dragged up a flight of stairs by some imps. Towards the end of the chapter, we see Martha's dead body being stuffed under a bed, her eyes still open, and her foot dangling above her head.
- Jennifer finds her in the next chapter with a bloody bag over her body. Her feet are still moving.
The very first imp that you encounter. At first, you can see it curled up on the ground crying, thinking it's child, until it turns around.
"The Mermaid Princess":
- It's made even worse once the player puts all the clues together. Clara is clearly being molested by Hoffman, who can be seen stroking her in bed right before the boss battle. Then you notice the stitching on her abdomen, and one of her attacks is to spew vomit on you.
When Jennifer first enters the orphanage, there is a shadow to her right just before the stairs. It looks innocent enough, especially since there's supposed to be a boy at the top of the stairs, until you realize that it's floating in midair.
"It's into the Onion Bag for her." Cue horrible, horrible children doing something utterly repulsive to Jennifer.
The children's bag masks.
Boss Hoffman, especially in a scene earlier in the chapter where you can have Jennifer peer into the locked sick bay and see imps controlling him.
- It's even worse when the player connects him to Sir Peter and relates it to the storybook at the beginning of the chapter.
  - Especially considering that Hoffman is a pedophile. Brings new meaning to the phrase "holding it in".
  - Even more creepy when you find a hat that looks exactly like Sir Peter's in Hoffman's closet.
Jennifer lost her parents in the airship crash, was then held captive by Gregory and dressed up like his dead son, probably spent some time in a hospital, came to an orphanage filled with sadistic children, and later witnessed their deaths at the hands of Gregory. What an unlucky girl indeed.
The first time you see a pig imp.
Wendy seems to be the only person who really likes Jennifer. Then you realize what she's capable of.
- Even Amanda seems to be okay with Jennifer until she passes her in ranking. Hell hath no fury like an obese British girl scorned.
The opening to the game sums up everything. If anything in that clip disturbs you, don't bother starting a new game. It only gets worse.
When you find out what happened to Brown.
The entire "Rag Princess Sews" chapter. First of all, the music in the level, unlike the other chapters that used pianos and strings in the background, is replaced with a Silent Hill-esque industrial sound. Second, being in the dark in such a huge place is not pretty. Third, having to chase "Joshua" in such long, dark hallways and having to battle several endurance rounds with the toughest enemy type is one of the scariest moments in the game.
Gregory might have been a cannibal, and the mention of "peas" in his diary could refer to children. Now remember that he tried to feed Jennifer pea soup...
And the enemies wearing severed pig heads. And the "Mermaid" boss. And the Onion Bag and the Rat Stick, especially when it's Jennifer's turn and she realizes the rat is very much rotted by now. And the scene with the ropes and the crayon gag and the storybooks AND the last two gifts...You know what, just put down everything about this game that didn't make you cry. And even some of THAT.
- "A bright red crayon just for you. A bright red crayon just for you. A bright red crayon just for you. A bright red crayon just for you. A bright red crayon just for you. A bright red crayon just for you. A bright red crayon just for you. A bright red crayon just for you. A bright red crayon just for you."