Best movie mistakes of 2011
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.
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).
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").
Factual error: In one of the first major scenes where Matt Franklin and Tori Frederking are being introduced at the rental store - there is a shot where you can see the entrance of the store, and there is an electronic article surveillance detector on either side of the entrance to the store. This technology for use in a video rental store (for VHS tapes) did not exist in the 1980s.
Plot hole: When Ethan meets the Secretary in the car, he tells him that Hendricks was seen leaving the Kremlin with the nuclear launch device and deduces that he is Cobalt. The Secretary then gives Ethan the flash drive containing his mission, which Ethan reads on the train. Ethan then tells the rest of the team that - according to the mission - IMF believes that Hendricks is Cobalt and was seen leaving the Kremlin with the launch device - hence why he needs to buy the launch codes from Moreau. How could IMF have known about this information to put it on the drive, given that Ethan just told the Secretary in the car?
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.