Trivia: Towards the end when Jim gives Batman the playing card in the plastic bag, the label has the name J Kerr. In some of the comic's backstories, Joker was actually called Joe Kerr. In others, it was a pseudonym.
Trivia: The playing card that Jim gives to Batman is the same card used by the Joker in the 1989 graphic novel "Arkham Asylum: A Serious House on Serious Earth".