Plot hole: If Bradley Cooper was able to "quintuple" his money every day in the market as he claims to have done, he would have been able to earn the $100k he borrowed from a loan shark within a few days, starting from $800. Alternatively, he is shown in one scene winning a pot in poker where he could presumably also make a large amount of "seed" money from gambling. There was no need to borrow such a small sum of money from a loan shark, making the entire sub-plot unnecessary.
Continuity mistake: When Brant kills Barry at the end of the movie, Brant lowers his gun after shooting him, but in the next shot he is pointing his gun at Barry. Also, the scene shows Brant holding a semi-automatic style handgun before shooting Barry, then when the scene pulls out it shows him holding a revolver, then shows him holding the semi-auto again.
Other mistake: In the pre-credit scenes when the chopper spots the runaway car, Driver guns it (he clenches his jaw, fists and you hear the engine revving and gears changing) but he never catches up with the two cars only a few feet in front of him (which are proceeding at normal speed) for the whole length of the bridge.
Revealing mistake: While Bishop and Steve McKenna are practicing with various firearms, a slow-motion shot in the film of Steve shooting a .50 caliber rifle shows that, while the sequence depicts him firing "live" rounds, the extracted shell casing is from a "Blank" cartridge (evidenced by the crimped forward portion of the brass casing). (00:34:15)
Plot hole: Through this film (and its predecessor) it is established that the creature imitates its victims perfectly, having all of their knowledge and memory. At the end, when the female lead tells the male lead she knew he was human because of his earring, he reaches for the wrong ear, confirming he is The Thing. Even if The Thing couldn't reproduce the earring, it would have known which ear it was supposed to be in.
Factual error: When Cattleya escapes through the sewer drain and winds up in front of the U.S. Embassy, she uncovers the manhole all by herself. Impossible for such a young child to do.
Deliberate mistake: In the final shot of the film, Jill's head moves slightly when she's supposed to be dead. (In the commentary, Wes Craven confirmed this wasn't strictly intentional, but he decided to leave the take in on purpose in case he decided to bring her back in a future installment. But unless a sequel proves she's still alive (Scream 5 does not), it's technically a mistake, albeit a deliberate one).
Factual error: Erik arrives in Argentina at a place called Villa Gesell, shown to be a town in middle of mountains. Villa Gesell is a beach town on the Atlantic Ocean coast, with no mountains.
Plot hole: No one wonders what happened to all the staff and patients at that sanatorium? No police ever came there and checked the place out after 30 years? And all the patient records, furniture, etc are still there?
Factual error: When the action moves to England after the failed award ceremony, the British Union Flag hanging from the wall is upside down. The broad white band should be at the top left (nearest the top of the flag pole).
Factual error: In the scene straight after the opening credits we are taken to Baker Street where construction work is being done. This work is identified by a sign with a logo as being for the underground line. The logo type face was developed by a Mr. Edward Johnston for London Underground from 1913 but the distinctive typeface used in the film was not in place until 1919. This is obviously long after the 1891 setting of the film.
Factual error: When a global map is shown, the location of Toronto is incorrect. What is labelled as Toronto is actually the location of Montreal. (01:08:05)
Audio problem: This scene is repeated multiple times in the movie: usually when the main character enters the "source code" the scene begins by panning over a small pond showing a Canada goose taking flight. However the sound editor makes the mistake of dubbing in a recording of a hen mallard duck.
Continuity mistake: After meeting Elise on the bus and getting his Blackberry dumped into his coffee David Norris calls his friend Charlie with his "spare phone" (silver). But after a cut or two you can see that he uses his BlackBerry again. So he has changed the phone during the conversation AND his coffee BlackBerry seems to be working again. (00:19:20 - 00:20:10)