Continuity mistake: In the scene where Tom is tasting wedding cakes he is sitting at a table with a blue box cake with white bow, but in the next shot a lady then places the cake on the table.
Continuity mistake: In the scene where Joaquin Phoenix's character is walking between a heavily wood-paneled wall and a window and banging on them: The first time he bangs on the paneling, one of the panels appears to split and swivel up showing white underneath. The camera briefly changes angles. When the camera returns to Joaquin Phoenix, the split panel is fixed.
Continuity mistake: Eden's hand and arm positions change between shots during the final scene in the movie, when she is kissing Adam.
Continuity mistake: When the Wolverines are attempting to get "the box", the Matt Eckert character is shooting through a window. When we see his point of view, there are blinds in the way of the camera, however every time it shows the actor, the blinds are open.
Audio problem: When Emily picks up the tooth from the box, she says "ew" but if you look in the mirror her lips don't move.
Continuity mistake: In the very beginning, the truck that hits the vehicle does so from straight behind. However, when they pan out, someone the truck is perpendicular to the crashed car. The snow tracks don't show the car that was hit swerving, and there aren't any tracks to show that the truck reversed either.
Factual error: The movie is set in the current time (2012), but Andy flies in an L1011 in the distinctive paint scheme of Delta Air Lines. Delta retired the last of their L1011 fleet in 2001.
Factual error: In one scene Drew Barrymore stands in from of a political world map, showing the political borders as of today. You can see the successor countries of the Soviet Union in that map. But the plot plays back in 1988, with the Soviet Union still alive.
Other mistake: When Christine is shot near the end of the film, there's no blood on her dress or the Phantom's hands.
Continuity mistake: When the mother breaks the window to enter the neighbor's house the next frame shows the glass still intact. (01:07:00)
Continuity mistake: Alexandre Lagarde puts his fork into the plate of the attractive client, much to the scorn of her husband. The morsel in close-up and the one she actually puts in her mouth are different. (00:06:10)
Continuity mistake: Tom walks into Anthony's memory. Anthony is sitting by the pool next to a table with two glasses of beer, which are 1/3rd empty. A few minutes later the memory is replayed, but this time both beer glasses are mostly full. (00:49:50 - 00:58:35)
Continuity mistake: While he is copulating with Laurence, François Monge receives a phone call from his boss about the murder case in Bobigny. To shush his vocal partner, he gives her a slap on the shoulder, but he does it with the right hand in the view from behind, and the left hand in the full frontal. (00:08:55)
Character mistake: It's said in the movie a vice presidential candidate never gave a concession speech. Geraldine Ferraro did this in 1984.
Plot hole: The killer has been living in the (apparently big enough) crawlspace between walls and floors, for over a decade. There is no explanation (or rationale) given on how he moved the various objects inside every room, closed doors, fed when the house was not occupied, hid the various corpses and, silly detail, concealed his own BO and the stench of his own living quarters, which is something hinted at when they find out his hideout. It is explicitly said that he is agoraphobic and does not get out, ever.
Continuity mistake: When Rory reads the first page of the manuscript found in the old briefcase, there is handwriting on the back of the first page facing the camera. The shot changes to the typed text and the handwriting cannot be seen through the paper. A few more pages into the story, handwriting can slightly be seen through a page that has nothing written on the back of it as seen by the camera.
Revealing mistake: Lazy prop department at work in the opening credits of this movie; look at the guest list. The second page and the first page are an exact copy and paste of the same names and addresses. (00:01:35)
Continuity mistake: Dinner at Forestier's home, and Georges Duroy does not know which knife to use to eat. The asparagi in his plate are across the small pie in the wide shot, and in close-up they are arranged entirely on the side without his intervention. (00:08:20)
Continuity mistake: In the intro, the mother is playing with her kid; notice that when she grabs the gladiator puppet she is holding it with the index finger above the shoulder in the wider angle, below in the frontal close-up. (00:01:00)
Factual error: Charlie was at Mayview State Hospital typing by the window. In the not-too-far distance, the University of Pittsburgh's Cathedral of Learning is visible. Mayview was located in Bridgeville, PA which is about 15 miles away, so The Cathedral shouldn't be visible. (Pittsburgh's terrain is hilly - not flat enough to see very far). (01:33:40)