Continuity mistake: When John comes to get Dawn and they leave Sally's house, the Chihuahua isn't with them, but all of a sudden it is back with them on and off throughout the movie. (00:05:45)
Visible crew/equipment: When R enters the control room where Cyper is waiting and the camera moves towards Cyon, you can see the reflection of the camera in the curved glass. (01:35:20)
Factual error: The film is set in the 1950s. In the scene where Ewan McGregor and Peter Mullan are waiting for a load of coal (the morning after they discover the body), there is a close-up shot of Ewan McGregor's head and shoulders. In the background is a huge container ship, slightly out of focus. Containers were not introduced to Europe until 1966 and the ship in this film was probably built in the 1980s.
Revealing mistake: When Lex gets out of the shower after his last training session, you can see his black briefs when he towel dries himself.
Continuity mistake: During the coverage of a bingo game, the caller said B-8. Immediately the shot changed to a player covering N-38.
Continuity mistake: As John first checks in at the Baker motel, the pen on the desk shifts between shots. It's on a chain and certainly would make some noise if either character had moved it. (00:10:45)
Factual error: At the beginning of the movie when Anthony Hopkins' character points out to the academic board the definition of "spooks" in the dictionary, it seems to be too close to the front of the dictionary to be in the S section. (00:07:10)
Factual error: Sean is tailing his victim, taking photos with an old Polaroid camera (the kind that prints instant photos). In one scene, he is sitting on a bench and takes several shots. When he shows these pictures later, some are zoomed in on the subjects, when it would not be possible to zoom with this camera. He would have had to get up and walk toward them, thus giving himself away.
Continuity mistake: When Colm Meaney and Colin Farrell have the shoot-out right at the end, the material filmed changes between then and when the director is viewing it at the end. First, Farrell shoots Meaney, then the camera goes to white and two more gun-shots go off. Then, when he is watching it later, Farrell pulls the gun from his pocket and the director shoots him straight away. Then when he rewinds it, it shows Colin Farrell pull his gun, the camera man look to the bonnett of the car where the gun is, then bring it up and shoot him.
Factual error: Throughout the film, most of the characters talk clearly underwater with the SCUBA mouthpieces in their mouths, which is impossible.
Continuity mistake: The runaway girl that is in Rory Culkin's class has a nose ring in her left nostril in the beginning of the movie and in her right nostril all the way through the rest of the movie.
Other mistake: Marian asks Winthrop to go pick up a book called "The Indiana State Educational Journal 1901-1910". When we see her reading the book, it actually says "The Indiana State Educational Journal 1890-1910". (01:08:25 - 01:13:50)
Factual error: In the opening scene, the German soldiers are searching the Americans. They remove a package of Lucky Strike cigarettes from one of the Americans. This package has the red circle against the green background. Green ink was stopped in 1942 because it uses chromium for green pigment which was necessary for war production of steel. Slogan "Lucky Strike Greens Has Gone to War" was a big advertisement in 1942 with introduction of white background on package.
Continuity mistake: In the scene when Halley just left from her counselor's office, Macon was going to go after her but the counselor stopped him. Then he was doing something with his hands and he had a pen. In the next shot, he sort of taps the wall, and the pen is gone.
Visible crew/equipment: At the end of the movie, when Hamo and Nina head off on the piano, watch the shadows on the ground to the right. You can see that a person is pulling the piano to make it appear that it is travelling on its own.
Continuity mistake: After they have sex for the first time, Adam and Evelyn are on the floor and she tells him to smile into the camera that was filming them making love. The camera however, is pointed right at them on the floor, not on the bed where the scene started and they had the actual sex. (00:32:20)
Factual error: When both Erica and Courtney are racing, you can see mountains in the background, although there are no mountains in Houston, their hometown.
Plot hole: Aside from the fact that you can't have a semi-automatic rifle delivered to your doorstep (except to an authorized dealer), there's also the fact that the weapon apparently was shipped with a full magazine. This is ridiculous. All the boy did was take the mag from the box to the gun and it started firing right away. One can assume they already had the ammo and filled the mag inside the house. This is countered by the fact that when he takes the mag out of the box, it is empty. Freeze-frame confirms there is not a single cartridge in the magazine before it is inserted into the weapon. (01:21:40)
Factual error: In the final gunfight, we see a close-up of Charley fanning the hammer and rapid-firing his six shot Colt Single Action Army nine times in a row. [Kostner has stated in interviews that this occurs because a short scene of him switching revolvers (he had a second revolver in his belt) was left on the cutting room floor. Still a mistake, but there's the reason.]
Deliberate mistake: After Emily talks to inspector Girotti she starts a record player. Then she walks over to the window, sees Werner in the garden, and decides to go down. Between shots she appears behind him, which is wrong, as the song from the record goes on, but it's most probably intended. (00:30:45)