Factual error: In a couple of scenes, most notably the one where Graysmith drives his kid to school, there are newer cars in the background than the year it is supposed to be. In this scene the car is a 1971 Chrysler, when the scene takes place in 1969.
Visible crew/equipment: When El Wray and the police arrive at the hospital as Dakota drives off, at the very back of the shot is the crane used for the lighting (confirmed on audio commentary).
Revealing mistake: When Jessica Alba is in the dentists room with the chipped tooth, it's very obvious she's wearing a set of false teeth over her teeth.
Factual error: The movie was meant to be set in Oregon, but it was actually filmed in Shreveport, Louisiana. In the scene that has Tracy leaving the apartment complex where Bafford (Mr. Smith) is, she is worried that she is being chased by a jogger who may possibly be Mekes. In the background, during the shot where the jogger first appears, a brown sign can be seen. These specific signs are unique to Louisiana and describe the history of certain locations, this one obviously being Shreveport.
Continuity mistake: The writing on Ghost's sword early in the film has the Turisas rune (representing TH in Thunder) near the hilt, but later not only is a different font used but now the Dagalas rune (representing the D in sword) is at the hilt.
Factual error: Hadrian's Wall is facing the wrong direction. The Wall was built to defend Britannia from the Picts in Scotland; therefore, its front should face north. However, as the Romans approach it from the south, they are greeted by the sheer face of the Wall.
Continuity mistake: When Michelle gives her pep talk to Coach Fields, the house they're in is the house they moved from at the beginning of the movie.
Factual error: The movie was set roughly in the early 1950s, but the two motorcycles were at least mid-1980s or newer.
Factual error: The movie depicts Wes Studi, who is playing the Paiute medicine man "Wovoka," as coming to the Sioux reservation and delivering his vision. Wovoka (aka Jack Wilson) was from Schurz, Nevada 1250 miles away from the Pine Ridge Reservation in South Dakota. He never travelled to South Dakota. What really happened was tribal parties (at great personal risk) travelled to Nevada to get the message and brought it back to the Sioux people. Of course, this message was "modified" somewhat to better fit Lakota culture.
Continuity mistake: When Fred gets to the North Pole and the Security elves take him down. Fred comes up and the snow on his face change between shots.
Continuity mistake: Right after they decide to become a team, Jim is walking to Hakeem's home and you see a little boy in a green shirt in three different places during the walk. The little boy is seen playing pattycake with a little girl on a car, then you see him running down the street and in the very next frame you see him kneeling at a flower bed.
Revealing mistake: There are 4 different vehicles in the movie that have the same license plate number (2PCE275). The first is on a white car owned by the gang member that shoots Max. Then you see the same plate number on the pickup truck of the skinheads that are harrassing Gary. Then you see the same plate on Steven Seagal's car as he drives away from saving Gary from the skinheads (incidentally, the front plate on his car is different than the back plate). The last time you see the same plate is on a Lexus driven by the guy in the all white suit who is going to buy the cocaine.
Continuity mistake: In the hospital scene, when Jenna's close up shot is show her a strand of her hair alternates from being in her face to off her face to back in her face. (01:30:05)
Continuity mistake: While discussing her bodily changes during adolescence, Marji says her left foot became enormous, but the scene shows her right foot growing larger.
Continuity mistake: Drew Barrymore's hair varies from shot to shot, as well as within scenes. It's always styled a bit differently, as if she did not have the same hairstylist more than once.
Continuity mistake: Right after Jim has his nightmare while sleeping in the car, he looks around for Grace, who is standing outside the car looking at scenery. When Jim sees her, she has her arms crossed over her chest. The next shot, with Jim walking around the car, she has her arms by her side, and immediately after, the shot with Jim approaching her, she has her arms crossed again. All this took place in about 2 seconds, not enough time to drop her arms and recross them exactly the same way as the first shot. (00:19:35)
Continuity mistake: In the bar scene, Alan gets soaked by Charlie's drink, covering his face, shirt, tie, and coat. But when Alex leaves he is completely dry and all the wet patches have just disappeared.
Character mistake: The endotracheal tube (breathing tube) was not secured to the patient. It is standard practice to secure this tube to the patient in order to keep it in place.
Continuity mistake: When Eddie is about to be interrogated by the Turks, he's tied up with his hat on. In the next shot his hat is off, and just as the Turk administers the truth shot he rips Eddie's hat of his head.
Factual error: The phone at the Peacocks house is too modern for the time - the cord going into the handset had a clip in cord versus being attached directly to the piece.