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 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 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: 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: Near the beginning of the film Bateman is at the bar where he says some nasty things to the woman bartender. He orders Stoli on the rocks but when the she brings him the drinks they don't have ice in them. (00:04:50)
Correction: Maybe the bartender didn't like Bateman and gave him drinks that she messed up on purpose. Bateman might not have noticed because he was getting off on his "fantasy".
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.
Corrected entry: The scene where Patrick Bateman is having drinks with his colleagues when they were discussing women, Patrick quoted Ed Gein saying when he sees a woman on the street he thinks of taking her out, etc., and what her head would look like on a stick. But in fact, Ed Kemper said that not Ed Gein, Ed Gein killed people because of his mother. (00:47:15)
Correction: Not really a mistake by the movie, but more by the character. Bateman, the character, might have believed Gein said the quote.
Corrected entry: When Bateman has just killed Paul Allen and is dragging him out of the building you can see the trail of blood on the floor where the bag is leaking. When he walks out the front door to the cab suddenly the bag is not leaking anymore. There is no trail of blood. (00:29:50)
Correction: That I believe is intentional. In the end of the movie, it becomes very questionable whether Bateman really did kill anyone at all. So in this case, if he did not kill Paul Allen, there couldn't have been a real trail of blood, just the one in his mind. Also, Louis Carruthers only noticed the overnight bag when Patrick was loading in into the cab's trunk and not that it contained something; the same goes for the security guard at Bateman's condo, who didn't take any notice of the bag, nor the trail.
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 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.
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.
Corrected entry: Throughout the whole movie in the scenes at the office, if you look out the window you can easily tell that the city view is a backdrop. The perspective is all screwed up. (00:08:50)
Correction: The overwhelming suggestion at the end of the movie is that the whole episode has taken place in the head of a solipsistic, self-regarding yuppie: Patrick Bateman (though none the less entertaining for that). 'Mistakes' such as this one simply illustrate the unreality of the situation.
Correction: There's no over the shoulder view from the cops. The closest cop had a revolver.