Continuity mistake: During one of the scenes when Brad Pitt arrives home, he is driving a Lincoln Town Car, not his Cadillac. This is the car that he doesn't get until later, when he steals it and drives home during the scene when they crash the cars into each other at the end of the driveway.
Deliberate mistake: When Brad Pitt is in his garage and cleans the spot on this collar, he should have turned the car's mirror to the left to see himself. Instead, he turns the mirror to the right so the camera can get a view of his collar. (Yes, it's a common filmmaking technique, to show viewers what he's looking at, but it IS still a mistake.)
Factual error: While John is crawling through the sewer pipes, Jane's monitor shows his GPS location as 47.28 N 12.46 W, 35 feet below sea level. This places him under the Atlantic Ocean, somewhat north of the tip of Spain - nowhere close to New York, or any other streets for that matter.
Continuity mistake: After the botched hit in Mexico, Jane returns to her office, a little beaten up, and her associates tend to her wounds. Particularly clear is an injury to her right shoulder - it has bled enough to mark her singlet top, and is covered by a large piece of plaster. Yet when she dances with John in the restaurant, only a few hours later, there is no sign of plaster or wound.
Revealing mistake: In the scene where Jane is trying to run over John with her car, she jumps from the driver's seat while John is in the back of the car. Right before the car crashes through the fence, you see John through the back window. You also see a head in the driver's seat, even though no one is supposed to be driving the car.
Continuity mistake: When John and Jane steal their neighbor's minivan (after their house explodes) and back out the driveway, an assassin jumps onto the back. John hits the brakes and the assassin falls off onto the ground beside the van. In the next shot it is implied that the van runs over the assassin (two bumps), but John has not turned the steering wheel.
Continuity mistake: During the car chase on the freeway, Jane forces one of the pursuing cars off the road by driving, with it, through those large barrels of water near freeway exits. Water cascades over the cars; one interior shot shows that it's virtually impossible to see through the windscreen. Yet in the next shot, a few seconds later, all the cars are completely dry.
Continuity mistake: When Pitt is chasing after Jolie, he crashes through a fence and fires his gun, hitting the car's windshield. To the left of where Pitt is, you'll notice that there's one rail missing in the middle. When he climbs through the fence to the street, the fence rail has returned, and the hole left by Pitt is now slightly wider, just enough for him to climb through.
Continuity mistake: When John and Jane are having breakfast on the floor after their huge fight, John eats something out of a tall silver container. He then puts it on the floor next to Jane, who picks it up and sticks a spoon in to get some of what's in there. It then cuts to a closer shot of the pair, and Jane is chewing on the food and putting the container down, even though she didn't put it in her mouth.
Revealing mistake: When Pitt is on the roof of Jolie's car, he breaks the window in order to get into the car. First off, when played in slow motion, the feet never do touch the glass before it explodes. Second, all newer vehicles have shatter proof glass both on the windshield and the side windows. In real life the glass would have just cracked, not blown out as it did in the film.
Continuity mistake: In the scene where Jane and John are driving the stolen minivan and fighting the BMW's on the bridge, the sliding side door and hatch alternate between shots of being opened and closed. Jane's hair flies around from the door being open, before it is ever opened for the first time. These changes occur between wide and close-up shots, and between Jane's and John's close-ups, throughout the entire scene.
Factual error: In the scene when Angelina Jolie and Brad Pitt are being chased by their headquarters on the freeway, Brad Pitt opens the trunk of the van they are driving in. In the type of van they were driving you can only open the trunk if it's in park and it wasn't their van, it belonged to their neighbours, so it wouldn't have any special treatment.