Deliberate mistake: When Harry drops the Monster Book of Monsters, in the first shot facing Harry's feet as the book chomps at him, he runs backwards a few steps and he stands at the foot of the bed. However, in the shot facing the fireplace, there is actually plenty of floorspace now, much more than other shots, between the rug and bed for Harry to continue to run backwards. (00:15:15)
Deliberate mistake: As Christine approaches the Phantom in his lair (just after he has abducted her), we see that she is wearing very dark black eye-shadow. Back in the dressing room after coming off stage, as she talks to Raoul, we saw her face in close up and she was not wearing any eye-shadow at all, even though the Phantom leads her through the mirror just after she has managed to slip on a robe over her undergarments and she has not yet changed to go out to supper (Raoul says she is to be ready in 2 minutes). Her hair becomes 'bigger' and wilder, too. The change in her appearance is a reference to her descending (voluntarily, I might add - he didn't drag her through that mirror) into the Phantom's dark existence and to her sexual awakening. (00:28:45 - 00:37:10)
Deliberate mistake: During the Trojan attack on the Greeks at the beach, before Hector and "Achilles" have at it, there are two separate close-ups of Hector's sword slicing across a man's face, who promptly spins around and spews blood. This particular man is enjoyed twice in two takes of the same shot, just before and after Odysseus' close-ups. Then as if that's not enough, a few shots later this spewing man is actually seen a third time, but this time from another angle. (01:42:30)
Deliberate mistake: Laser beams are normally not visible, except for a small dot where they hit a surface. Even if made visible, using smoke or dust or special glasses, they are thin as threads. Obviously something more visual was needed for Toulour's dance act, hence the thick beams of light.
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: 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: Old Weird Harold's pants fall down twice in the film. His boxers are different colors each time; once they're red, the other time they're blue. The director admits to this deliberate mistake in the commentary, siting his interest in seeing if people will notice.
Deliberate mistake: It wasn't Mike Eruzione shouting his own name that finally convinced coach Brooks to stop making the players do sprints. It was Mark Johnson, who smashed his stick against the glass in a fit of rage.
Deliberate mistake: Frankie's voice-over reading of the letter to his father does not match the text of the letter. He says, "Ricky Munroe told me. Trust him to put his big feet right in it. I've told him hundreds and hundreds of times." but the letter reads, "Ricky Munroe told me. Trust him to put his size threes right in it. He is rubbish at secrets. I've told him hundreds and hundreds of times." (00:21:15)
Deliberate mistake: When Alexander is giving his pre-battle speech at Gaugamela, some of the shots are 'flipped', which has the odd effect of suddenly making all of the phalanx pikemen left-handed.
Deliberate mistake: In the scene near the beginning of the movie where Ben finds the pipe and finds the message by rolling the pipe on the paper, the message is long and has symbols, but it is impossible for all of that to fit in the pipe. (00:12:00)