Deliberate mistake: In the beginning, the police chief says "The six members of the family were found last night, in bed, shot and killed." As he says this, look to the left of the screen. In the background, the real Amityville house (dark brown with white windows and trim) is shown instead of the house used in the rest of the film. That segment was from actual news footage of the murders from 1974; apparently, the director didn't want to recreate it.
Deliberate mistake: In the scene where T& L are being pulled over for speeding, when they park, you see no protective rails on the side of the street they are on, but after they put the officer in the trunk and return to their car, on the passenger side, the rails are very visible.
Deliberate mistake: During the dance number in the Dead Bar, the blue pirate has a sword stuck through him with the handle in the front, later it changes to the back, then to the front again. Seen when the groom falls back and grabs the handle, then picks the pirate up and drops him. (00:19:15 - 00:20:05)
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: Geologically, the type of volcano in the movie shouldn't erupt so much low-viscous magma; but due to make the volcano exciting to the audience, the movie makers probably deliberately ignored this mistake.
Deliberate mistake: As the Soviet tank starts rolling, the tank commander obviously uses a hidden step to mount the tank. Soviet T-55/T-62 type tanks did not have steps for mounting by the wheels and axles; to mount a rolling tank using the moving wheels or spinning axles would result in the mounter being immediately crushed and killed.
Deliberate mistake: When the truck is slamming numerous parked cars on a residential street, it sideswipes a parked Dodge Aspen (white with tan landau top). At the lower-right corner of this shot, a white Chevy Nova is parked at the corner (its vinyl top and trim has been poorly painted the same white as the body). Both these cars are repositioned to be at the roadblock location at the end of the chase, with the Nova slammed from behind by the truck and the Aspen parked near the cop cars. (00:07:00 - 00:07:40)
Deliberate mistake: As the horse named "Sir Trenton", who is supposed to be a stallion, is galloping away you can see that "he" is a female.
Deliberate mistake: When the heads of the families assemble in the Palazzo Azzuro in Atlantic City and get attacked from a helicopter the rotors make the glasses on the table shake and the piles of fruit in the bowls collapse. As the Palazzo looks like quite a solid building this effect is a bit exaggerated. (00:59:35)
Deliberate mistake: The Studebaker in which Carol is first riding bears the license number JPM 351, which interestingly enough, is not only the same license number that Steve's 58 Chevy has, but is also worn by the car Curt is sitting on when he first meets the Pharaohs. To top it off, the Edsel driven by Cindy Henderson has plates reading PRC 596, which are also used by a silver 57 Chevy and a red pickup.
Deliberate mistake: When Fagin shakes Oliver's hand (when he first meets him) there is a blonde haired boy standing right behind Oliver, but in the shots from behind him, the boy is gone. This may be because the camera is just behind where the boy was and he had to move so they could get the shots from this angle.
Deliberate mistake: When Red is shooting at Crews and Crews forces him off the road, the driver's front tire blows on Red's truck. You see it happen and see the blown tire again when he goes off-road. A few seconds later, Red drives away as if there is no problem. (00:58:05)
Deliberate mistake: When Lucius is shown Maximus' tomb, the painting on the wall reads, "What we do in life echoes in eternity," in plain perfect modern English language. Of course, it helps audiences relate to the first movie, but it's ludicrous, to say the least.
Deliberate mistake: Marian is wearing pantaloons, or knickers, in the rape scene. Knickers were not worn by women until Victorian times, and then they were split at the crotch.
Deliberate mistake: Joseph (John) Merrick's speech was never as audible as shown in the film, and several operations were needed before he could speak at all. Even after that, Frederick Treves often had to "translate" what Merrick said because the majority of people still had problems understanding him. [Probably changed to simplify the storytelling, but still inaccurate].
Deliberate mistake: When the two Confederate and Union soldiers meet across the river and trade coffee/tobacco, you can see the other side of the bank behind them. It looks at least 50 feet away, yet before they were able to talk to each other without shouting. Also, the Union soldier raises the pipe to his mouth in his right hand, which switches to his left in the next shot. There is also a mist present at the beginning and end of the meeting, but not in the middle. (00:37:55)
Deliberate mistake: Rather than using real Bruce Lee footage only for the final fight scenes, so the undisguised Billy Lo's different appearance might make sense after his surgery, the filmmakers instead spliced real Bruce Lee face footage throughout the early film giving the character a constantly changing face from scene to scene.
Deliberate mistake: When Cady is breaking the 'plastic' crown into bits and throwing the pieces to people in the crowd, it's not possible to have that many pieces from that one crown. She must give out at least 7 or 8 big chunks, which just doesn't truly reflect the size of the crown.
Deliberate mistake: The extras used in the scene when Danny gets assigned the case appear again as members of the jury. If Danny's colleagues were called as jury members for a trial all would have to declare a conflict of interest and be ineligible to hear the case. (00:09:30 - 01:03:25)
Deliberate mistake: When the geek and the prom queen are driving along in the Rolls-Royce rebel yell scene, the close-up shot of them through the windshield shows a missing rear-view mirror. It was there when the geek pulled out of Jake's garage and it reappears later when the Rolls is parked in front of the house where John Cusack's character lives. This was probably a deliberate mistake by John Hughes so that he could get a better shot of the prom queen feeding birth control pills to Anthony Michael Hall.