Revealing mistake: When the doctor with the satellite phone runs to the car, he is being chased by another member of the team, and of course the graboid. Look ahead of the graboid. The path it will take is visible.
Revealing mistake: The bottom third of the left-hand side of the screen is a "filler." At the top part of the left-hand side, there's a bicycle hanging on the wall, a square wall shelf, and a 3-Light Tree Floor Lamp. About two-thirds of the way down the wall, there's an inverted image of the items at the top - the angled edge of the wall (which does not line up with the rest of the wall because it's inverted), half of a bicycle wheel, the square wall shelf, and 3-lights of the floor lamp at the bottom of the pole. (00:01:54)
Other mistake: A female bull shark has between 1-13 pups. The exact number in the movie is questionable (due to their speed), but appeared to be well over the maximum 13 and perhaps closer to double this amount. Classified as "other" instead of "factual" mistake because the mother shark's DNA was altered, which could possibly explain a higher number of pups per pregnancy. (01:03:20 - 01:06:40)
Continuity mistake: A-X-L frequently varied in size. For example, sometimes its head looked massive compared to Miles, being about the size of Miles from his head to waist. Other times, A-X-L's head looked about twice the size of Miles' or Sara's head. A-X-L's body was sometimes about the same size of Miles' motorcycle but much larger other times. A-X-L looked much smaller when it was dragging Sam compared to when it was standing over Sam.
Continuity mistake: When the boy is given the gun and bullets so he can go and find a temple to cure his mother, he has a handful of bullets and one slips down and falls into his sleeve, partly sticking out. It cuts to his face and then back to his hand from a different angle. He has his hand cupped still but you can tell it's empty with no bullets in it. Also his gun keeps changing positions in his other hand in each shot. From pointed down, to pointed straight up, to pointed to the side. (00:17:15)
Continuity mistake: In the first WW2 flashback the protagonist is handing the various items to the Nazi doorman. When he puts down the pen, he is doing it with a left hand in the table close-up, but he picked it with his right, as the left arm is busy holding the coat. (00:02:05)
Continuity mistake: When Stallone kills the bad guys with skull masks in the corridor of the bar, his motions pointing the pistol don't match the positions of the lemming-like goons he hits. For instance he has the gun all the way to his right for the first one he kills, but the guy is shown with a hole opening in his forehead while he's in the middle of the corridor. (00:29:00)
Character mistake: Immediately after the crash, when Reeves is carrying his youngest child Sophie, the actress opens up her mouth, even though she has already drowned. (00:14:43)
Factual error: Cat Rivers is flying the R44 helicopter from the left seat. The R44 is a single pilot helicopter fitted with dual controls. Two collective levers may be installed (the left is removable) but the cyclic control is not of a conventional nature. This comprises a central stick terminating in a pivoting T bar, which only allows one of the pilots at any one time to control the cyclic with the hand grip in the 'normal' position. The R44 is normally flown from the right seat; it is possible to fly from the left seat and instructors regularly do so. Students and low experience pilots would normally only fly from the right seat, and are discouraged from flying from the left seat when with friends. This is because of the unusual cyclic control configuration and, to some extent, the different instrument scan and visual references for hovering when flying. (00:14:40)