Nightmare Fuel / Kingdom Hearts: Chain of Memories
That's right folks, a Disney game with the personification of death itself.

  • Sora slowly losing all of his memories, specifically replacing Kairi — one of his best friends — with Naminé, was rather disturbing. The depth of his brainwashing was made most explicit when Sora begged Naminé to break his heart to save herself, knowing that she'd been manipulating him the entire time and that he'd probably end up catatonic, staring at nothing just like the Riku-Replica.
    • The whole concept of losing one's memories the further into Castle Oblivion they go is pretty heavy Nightmare Fuel all on its own. Sora's gradual descent into madness just makes it even worse.
  • Naminé is deathly afraid of her captors, Marluxia and Larxene. Larxene is known to revel in cruelty, and Namine's reaction suggests that it may not all have been shown on-screen. Even more disturbing is her obvious terror whenever Marluxia is around. The way she jerks away when Marluxia touches her on the shoulder just makes it worse.
    • When Larxene slaps her out of the way in the remake, Naminé is visibly cowering with her arms raised to protect her head.
  • Vexen's death in the manga. We're treated to a glorious two-page spread...of Axel punching a hole through Vexen's chest.
    • Vexen's death in general, which has two other versions. The original GBA version has Axel cutting his throat from behind. The PS2 remake/PS3 HD ReMIX versions have him gloriously burned alive.
    • What about Zexion's death? Him being used by Riku Replica when he wanted to control the real Riku, and all of this was plotted by Axel who for an emotionless nobody seemed to...enjoy it.
  • How about that scene where Aerith flat out tells Sora that she doesn't exist? And Goofy and Donald don't see her?
    • Seriously, what's up with that? Was Naminé descreetly trying to warn Sora? Was it Aerith's own mystic-ness bleeding into her illusory duplicate? Was Sora already just going nuts? We never know.
  • This game in general is far Darker and Edgier than the previous game, and in fact arguably outstrips every other game in the series. There's a lot of violence, and Sora slowly loses his mind with his obsession for Naminé, and outright abandons Donald and Goofy when they ask him to stop and think about it.
  • The final floor is pretty darn terrifying, with the eerie music and it being The Very Definitely Final Dungeon and all.
  • Larxene. The woman's sadism is essentially a kid friendly version of Ramsay Snow's, not to mention Naminé's terrified reaction to seeing it in action.
  • Marluxia's third form (pictured above) looks like something straight out of a horror game; the music and the arena we fight that thing in doesn't help either.