These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Arkham Asylum A Serious House On Serious Earth
Harsher in Hindsight: The Joker's crack about Robin was written before Jason Todd had died in the regular books but the book came after. Morrison noted all it did was add another layer to the Joker's audacity in saying it.
Nightmare Fuel: The scene where Amadeus Arkham found the mutilated bodies of his daughter and wife in an upstairs room, who were murdered and raped by the Serial Killer Martin "Mad Dog" Hawkins. Arkham found the head of his daughter inside her Doll's House.
The portrayal of villains like the Joker and Clayface, who in this comic appears as a naked man whose skin is literally wasting away and who wants to "share" his disease.
The scene where Batman Batman breaks Clayface leg when he tries to "share his disease" with him.
At the beginning of the story, a young Amadeus Arkham brings his mother's dinner, only for the old lady to respond "I've eaten" several times, as several beetles fall out of her mouth.