I just back from seeing Joker. Liked it a lot.
MILD SPOILERS FOLLOW:
a) I noticed a Batman reference, specifically a 1966 Batman tv reference, that I haven’t seen anyone else comment on: namely, when we first meet Bruce Wayne, he slides down a pole.
b) I’ve read several reports saying that Alan Moore’s The Killing Joke is the only story from the comics that they drew significantly from. Not so: the whole talk show appearance scene, including kissing the fake Dr. Ruth, is directly inspired by a scene in Frank Miller’s The Dark Knight Returns (even if the resulting body count is a bit lower).