Revealing mistake: In the news reel detailing the Kohinoor theft, a few headlines appear, and at least one persists on screen long enough to easily spot the inconsistency between headline and article (filler text presenting a new local magazine from the London district of Lambeth). (00:09:00)
Revealing mistake: When the woman is tied to the bed, she is holding the ropes, and the rope isn't tight on her right hand; she can easily escape. (00:20:10)
Revealing mistake: When the stewardess asks April to sign her copy of the book entitled "How to Survive a Sharknado and Other Unnatural Disasters..." it's a thin book, and in the closeup as April autographs the page we can read the text and it's actually one of the versions of the "Samsung Galaxy Tab...For Dummies" book, not April's book. Also notice when Kelly Ripa shows April's book to the audience, it's now at least 4x as thick.
Revealing mistake: During the plutonium heist, when the truck skids, tire marks from previous takes are visible on the pavement. (00:10:20)
Revealing mistake: When Tom and Anna were jogging on a dirt path, the woman going in the opposite direction who passes them on the right would be walking straight into the kids (and woman) who were running past them on the left - but the woman on the right disappeared behind Tom's back where the collision would have occurred if she were really there. [Use of a green screen]. (00:29:25)
Revealing mistake: JR is in the weapon container of the crazy dealer, who passes him some of his goods. JR ends up holding in his right arm a MP5K and an M4A1, which combined are about 5 kilos, but then he passes him an M60 Machine Gun, which weighs over 10 kilos and that the relatively diminutive protagonist just handles throughout the scene gripping it with his left hand and making no effort whatsoever. (00:25:20)
Revealing mistake: About seven minutes in, during the scene where we see Cooper helping the Nerd as a cameraman, you can tell that Cooper has been added to the scene using green-screen effects, as the actor was unavailable to shoot at the location. The lighting on Cooper doesn't quite match the lighting of the scene, and you can see a slight "blur/feathering effect" around him where the greenscreen background was removed.
Revealing mistake: At the end the sides of the grave (which Jack just had dug by spade) are too perfect. Only an excavator could get such neat sides.
Revealing mistake: When the camera pans across John's family sitting on a pew, there is a few to several inches between each body. The almost-still frame closeup view from John's end shows the bodies cramming/overlapping and the first four are blurring. (00:11:03)
Revealing mistake: When the tanks are firing on the building near the end, some of the shots of shells hitting the building are reused. (01:35:00)
Revealing mistake: When James is getting on the St. Charles street car at Carondelet it's raining, but on the north side of Canal St, people are walking in shorts and with no umbrellas.
Revealing mistake: Crawling through a fire cave you can see propane bottles in the background several times.
Revealing mistake: In the scene were Viago is showing the locket that his girlfriend, Katherine, gave him, he puts it on, and since it's silver, it starts to burn his skin. The smoke from his burning flesh is coming from something on the table in front of him, not from inside his shirt.
Revealing mistake: Late on in the film; Arnie and the female officer kick in the door to one of his teams house. Unfortunately Arnie is in his 70s now and not as agile as he used to be, the door was open and simply pushed hard. Look at the door, it has no damage and neither does the frame. Also, the door barely opens past a hard push. As tactically trained operatives they would not have pushed the door if it was ajar either, they would have opened it slowly to avoid startling anyone inside and warning them.
Revealing mistake: Most of the tank battle scenes throughout the movie are low budget CGI.