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.
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.
Factual error: After the train crash, the teen characters discover cube-like items. One of them states it looks like a Rubik's Cube. The movie itself takes place in 1979, but the Rubik's Cube, although invented in 1974, was not licensed to sell in the USA until 1980. It was not even called a "Rubik's cube" until 1980 (prior to this, it was known as a "Magic Cube"). (00:21:55)
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.
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)
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.
Plot hole: One of Snape's memories show Lily telling baby Harry to be safe, be strong. That had to have occurred before Voldemort killed Lily. Snape was not in the house until after Lily was killed and Voldemort was gone. Only Lily and Harry should have had that memory, but not Snape.
Continuity mistake: When they get to the beach to surf the windows in the truck are left open, but after the shark attack Byron comes running back to call 911. The windows are now closed, so he has to throw the rock at the window and get the cell phone.
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?
Continuity mistake: When Johnny and Kate are having dinner in her apartment and Ambrose knocks on the door, Kate puts all the dinner away leaving a few candles on the table. The table is still like this when Kate and Ambrose leave the apartment, but when Johnny notices that the killer cleaner is in the apartment, the table is set up again.