Character mistake: The professor identifies the "sea monsters" as plesiosaurs from the Pleistocene. Plesiosaurs became extinct at the end of the age of dinosaurs, nearly 60 million years before the Pleistocene. Of course, the Loch Ness Monster might be an exception.
Revealing mistake: The El Camino that is going over the cliff, which has just been shot in the tailgate with a 50 caliber rifle, has no tailgate damage. Also at the same time stamp, when the El Camino is upside down, it is obvious there is no transmission or drive shaft in the car. They even show you this with a close-up. (00:46:20)
Factual error: During the opening credits. An LCD screen is shown with lat/long coordinates. The movie takes place in the Persian Gulf. The coordinates are in the vicinity of Oceanside, CA.
Continuity mistake: When King is fighting with Lazarus in the bar, Lazarus gets blood near his mouth like you get when getting hit in the face. But when they fight near the white door, the blood is gone. (01:13:00 - 01:18:00)
Factual error: The passenger cars are riding on 20th Century Bettendorf freight car trucks.
Continuity mistake: At the end of the film, Nicolas Cage assaults the enemy compound with two Glock 17s. When he exits the compound and shoots at the boss's car, which is pulling away, in one shot he is firing a SIG P226, but in a later shot is using a Glock again. (01:28:55 - 01:29:45)
Factual error: The bar shown in Iqualuit is not real. Iqualuit only has 6100 or so people, and there is no bar like the one shown in the movie. The building is wrong - it doesn't even look like any buildings in Iqualuit. There is one bar that looks nothing like the movie, one Legion, and a bar in the hotel in Iqualuit.