Corrected entry: In the scene where Bateman is in the shootout with the police, there is a shot looking over the left shoulder of the policeman at Bateman. While they are shooting, the gun is visibly out of bullets because the slide is locked back, however it keeps shooting anyway.
Corrected entry: In Bateman's office when the detective is first questioning him, there is a big white phone on the window ledge behind Bateman. In the next shot the phone has disappeared.
Correction: The phone doesn't disappear, the angle at which we could see it changes. The first shot of the phone is from higher up, we see it sitting in front of Patrick's briefcase. The shots of him thereafter are more directly-on and the briefcase is just hidden by the corner of his chair, thus so is the phone. At a couple of angles, you can actually see the phone reflected slightly on the shiny briefcase and we see it fully again at a later angle. It's never gone from the scene, just less visible.
Corrected entry: In Detective Kimball's questioning Bateman, Bateman mentions that he has a lunch with Cliff Huxtable in 20 minutes. Cliff Huxtable was the name of Bill Cosby's character on "The Bill Cosby Show," a popular series on at the time of the story. Furthermore, Kimball mentions that a Hugh Ainsworth spotted Paul Allen in London. Hugh Ainsworth is a popular crime author.
Correction: Detective Donald Kimball actually mentioned a "Hubert Ainsworth," and it wasn't Hubert who spotted Paul Allen, but rather a Stephen Hughes mistook Hubert Ainsworth for Paul Allen.
Corrected entry: In the scene where Pat Bateman is about to murder Paul Allen, we see Bateman take a pill and some water, then go pick up an axe. He picks up the axe with his right hand, then makes a move toward the door, without switching the axe to the other hand. In the next shot, he dances out behind Paul Allen, with the axe now in his left hand. (00:27:50)
Correction: The image of Bateman in that scene is the mirror's reflection, so it only appears that he grabbed the axe with his right hand.
Corrected entry: When Patrick has just killed Paul with the axe, he goes to Paul apartment and leaves a message on his answering machine and ends the message with the quote "hasta la vista baby", which is a line from the 1992 movie Terminator 2 Judgement Day. American Psycho was set in the 1980's.
Correction: "Hasta la vista" is a Spanish phrase that means, roughly, "see you later". While, yes, the phrase was famously used in T2, it didn't magically spring into existence for that film, so there's no reason why Patrick can't use it.
Correction: "Hasta la Vista baby" is the quote, and that is from T2. If Patrick just said "Hasta la Vista," then it wouldn't matter. But since he said "baby," it makes it a mistake.
I would agree with the refutation of the correction, but even "Hasta la vista, baby" is not a phrasing unique to Terminator 2. There is a whole Wikipedia page about it with previous usage, the most notable and likely suspect being its presence in "Looking for a New Love" by Jody Watley, which was a #1 hit in 1987, so appropriate for the movie timeframe. It'd be off by a week or so being an early January release and the scene taking place on December 20th of 1986 if we want to be pedantic.
Corrected entry: When Bateman is dragging Paul Allen's body out of the building, you can see a trail of blood leaking from the bag. When he gets outside there is no more blood trail or blood trailing.
Correction: Already submitted and corrected. The movie insinuates that Patrick is only fantasizing about all the murders and intrigue to make his menial life seem more interesting. Thus the disappearing bodies and no aftermath to his wake of killings and a police shootout in the climax.
Corrected entry: When Bateman picks up the two escort girls and takes them to his apartment he asks them if they like Phil Collins. At that time he turns on a song called "In too deep". For some reason this song starts at the chorus, 1.05 minutes into the song instead of starting at the beginning like it's supposed to. (00:42:15)
Correction: CD players have a function where you can skip ahead to a particular part of the song. Either Bateman skipped forward to that part right then or he set the CD player to that part before picking up the girls.
Correction: There's no over the shoulder view from the cops. The closest cop had a revolver.