Deliberate mistake: This was probably done intentionally to make them more visible, but the bullet holes left in the stairwell wall by Bart's handgun while he is chasing Danny during the movie's climax look to be about the size of golf balls. Typical handgun calibers aside, just looking at the size of the clip he's loading into the gun and seeing how many rounds it holds, those rounds would have to be much smaller than the holes the bullets made.
Suggested correction: It's a 9mm Glock18. The standard magazines have 17 rounds, the long ones 30. The holes could be larger because it's an old building and the plaster might break apart differently than modern drywall.
Deliberate mistake: After Carmen rescues Juni on the boat/sub, he accidentally re-engages the autopilot and they submerge. In the next shot as two Thumb Thumbs jump off their speedboat, the name, 'Donzi', that is written across the side of the boat, is backwards. This shot is flipped. (00:24:10)
Deliberate mistake: During the chariot race, the chariots crash together but the arrangement of the horses make it impossible for them to actually collide. In some instances (particularly in an aerial shot as Ben Hur and Messala round the turn) it is obvious that they repositioned the shaft of the chariot to between the first and third horses instead of being in the centre between the second and third.
Deliberate mistake: In the scene where the Punks follow the Warriors into the bathroom, Rembrandt sprays the head punk with his red spray paint. However, the spray coming out of the can is clear, not red.
Deliberate mistake: When Prince Hapi says that Monique should be his seventh wife, she says "you have seven wives?" and he confirms. Actually if she is supposed to be his seventh wife he only has got six wives by now.
Deliberate mistake: In a lot of the shots in the cockpit, when Teri is attempting to begin taking control of the aircraft, notice the Horizontal Situation Indicator on the First Officer's side. The compass rose is moving around erratically - which would suggest that the 747 is also changing heading extremely erratically and robotically - which isn't possible.
Deliberate mistake: In the opening credits, there is a newspaper article showing that Dirk Pitt has found the remains of Nungesser and Coli's L'Oiseau Blanc, a plane that disappeared attempting to cross the Atlantic in 1927 before Charles Lindbergh made it. The wreckage in the newspaper photo is totally wrong; it has a radial (round) engine and cowling and a three-bladed propeller. The real plane had an inline engine, square cowling and a two-bladed propeller.
Deliberate mistake: In the scene where Frank and Jazira are trying to escape from the evil sheik, as they ride towards the gate to leave the town, the gate is closed and bolted, locking them in. The bolt is located on the outside of the gate, facing the desert, instead of inside the gate to protect the town.
Deliberate mistake: They keep using the same footage of Bela Lugosi walking in the cemetery, even the cars driving by out on the road are the same. (00:53:00)
Deliberate mistake: When Boyd has saved the Vice President's life after chucking him into the water, Boyd looks down at the VP who is being dragged out. Suddenly, there is a picture taken that appears in papers, but there was no press or person on the bridge where Boyd is with a camera, so where did the photograph come from? (00:06:55)
Deliberate mistake: When Bond is fighting Zhao in the clinic, they accidentally set off the tomograph Zhao was lying in. As this machine's powerful magnetic fields indeed would pull any metallic object in, no doctor with common sense would allow sharp objects and other stuff within range. You aren't even allowed to carry watches and have to report any dental fillings. (00:43:50)
Deliberate mistake: The Fremen wear "stillsuits" to conserve their water, yet leave their heads completely uncovered. This would result in quite a bit of water loss through perspiration. (In the book, they wore hoods, masks and nose filters, leaving only the eyes uncovered, but it wouldn't work in a movie to have all the actor's faces obscured!).
Deliberate mistake: After the airplane loses its propeller and descends to lower altitude, the cockpit constantly shakes due to turbulence, and the flight crew complains about it in one scene. However, when the camera switches to the passenger cabin, everything remains perfectly still and serene until the airplane is on its final landing approach near the end of the movie.
Deliberate mistake: This is a mistake which is a function of the limitation of the special effects at the time and what the censors would allow in the cinema but the wounds suffered by the Zulus do no justice to the horrific injuries that the Martini Henry rifle would have caused. The Martini Henry fired a big .45 inch soft nosed bullet that usually shattered on impact. It would have caused massive gaping wounds rather than the little red dots and trickles of blood shown on the Zulus and left many of them limbless as the bullets tore off arms and legs.
Deliberate mistake: When the recon team head out of the base they encounter a robot. But it is a probe droid, distinguishable by the lack of a cannon on its right arm. The only probe droid that the lab sent out self-destructed back in the 1970s, the rest were all sterilisation units. (00:39:05)
Deliberate mistake: In the scene where they break into the train from its roof, you can notice that despite the high speed and the consistent wind, Captain America's fellows have no difficulties in running, standing up still, and even jumping, like they felt no air resistance. Moreover, you can see that their hair is not moving at all, completely missing to realize any "windy" effect.
Deliberate mistake: Polly's and Sky Captain's clothes are discarded because they are contaminated with uranium; however, Polly gets to keep her camera. Her camera would have been contaminated with uranium, too, because she had it with her in the underground cave.
Deliberate mistake: When Arthur follows Guinevere to the meeting with Merlin, her and the trees' shadows point at the viewer. Only Arthur has two shadows, one points to the left. The source of the moonlight is below the next ridge, and it's bright like a floodlight. Later, when Arthur is talking to Merlin, his face is always illuminated, even after a 180°-turn. (00:59:00)
Deliberate mistake: When Raza is chasing the "empty" train, as it goes over the trestle just before he stops it, you can see the engineer in the train's engine.
Deliberate mistake: Whenever we see the computer generated Lou, he never has genitals.