Factual error: When the Ranger trainees first meet Samuel L. Jackson, he's wearing the rank of a Specialist on his collars even though he's a Master Sergeant. Title 18, Chapter 33 of the US code prevents the unauthorized wear of a military uniform (among other things), however this does not automatically correct the mistake since a common misconception is that one slight alteration is sufficient to make the uniform legal. Having the wrong rank on is too obvious of an alteration, especially for anybody who has spent more than a day in or around the Army and would still be punishable by law, if he was dressed in an attempt to fool your average citizen outside of a movie.
Revealing mistake: When John Cusack is driving the actress, there is a shot looking over his right shoulder at the dashboard. The speedometer reads 0 mph. (00:08:15)
Continuity mistake: In the scene where Stanley and Zero are digging to find the chest toward the end of the movie, the background behind them is just a dirt wall. In a following shot upon discovering the box, there are stairs that lead to the hole. In the next shot, these stairs are gone again and it's just the hole again. (01:38:05)
Factual error: In the scene at the beginning of the movie as the 3 youths walk up the street, you can see current MA license plates, although the action should have taken place many years earlier. (00:01:30 - 00:05:50)
Factual error: When Shorty is removing Jennings' memories in the beginning, the pictures shown are from a third person viewpoint. If they are his memories, shouldn't these be from Jennings' viewpoint? (00:06:40)
Plot hole: In the scene where she goes to her house after escaping there is no police tape on the front door even though it is a crime scene. Earlier the police searched and taped her office - it only makes sense that they would do the same to her house.
Continuity mistake: In the scene where Eddie Murphy is going into the crypt, he takes one of the lit torches. While they are trying to escape the skeletons, the door to the crypt closes and locks. When they show the shot of his son outside, you see two torches again. When he gets the doors open and they leave, you see one.
Factual error: When young Ichi is hit in the face with the baseball, he doesn't react realistically. He simply falls back spitting blood, when in reality, he would have been knocked out and probably lost a number of teeth, and perhaps even broken a bone in his face.
Continuity mistake: When Cassie sits down at the table at the pub there is a menu lying next to her glass. When it cuts the menu has changed position. (00:22:00)
Visible crew/equipment: When the Zombies are chasing Greg in the woods, one of them leaps through the air. You can see the springboard he does it from. (00:45:25)
Deliberate mistake: There is one scene in the movie where Heath Ledger reads a Latin sentence in a book. As he is translating the sentence, he goes over the words one by one with his finger. This would never be possible in a Latin sentence, because words in Latin are never in exactly the same order as in English. Words that actually belong together can be placed at opposite ends of a sentence.
Continuity mistake: Julie doesn't come home one night; the next day as she is getting out of the pool we see that she has been "roughed up" and has a black eye. Next to her eye there is a circular bruise/mark. That evening, as Julie and Sarah are at dinner the bruise is now under Julie's eye and is a different shape (longer and more oval in shape). (00:52:50 - 00:58:00)
Continuity mistake: In the scene where Frannie and Detective Malloy are standing outside the police car, after Frannie was picked up by the two police officers, outside her apartment, you can see a girl with a white shirt with black sleeves and a very short skirt passing by. After a few seconds, Detective Malloy goes back into the car and you can see the exact same girl passing by at the same direction as before and she even wears the exact same clothes.
Revealing mistake: When Dae-su enters the room of one of his nemesis, his computer screen shows information about the stock exchange. The Internet address on the screen is: C:/DocumentsandSettings/[.]/OldBoy/[.], which would be a link to a folder on that computer, not an Internet address.
Factual error: There is one scene in the movie where Heath Ledger reads a Latin sentence in a book. As he is translating the sentence, he goes over the words one by one with his finger. This would never be possible in a Latin sentence, because words in Latin are never - I repeat: never - in exactly the same order as in English. Words that actually belong together can be placed on opposite ends of a sentence.
Continuity mistake: Curtis is helping Molly seal the windows by screwing them shut. He hands the drill to Molly and she holds it up by her chest. When Claudia walks into the room Molly lowers the drill down in front of her below her waist. Then there is a quick cut back to Molly and Curtis as he says, " well that should do it", and the drill is back up in front of her chest again as she lowers it down a second time.
Visible crew/equipment: When they unearth the cadaver, you can see in some shots that he wears a blue string. One of the men even sees it and tries to hide it subtly.
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)
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)
Continuity mistake: In one scene, Rabbit picks three flowers. In the next shot, Rabbit gives all of the three flowers away and still has one for himself without ever having gone back to the bush to pick one more for himself.