Revealing mistake: When Eric Matthews is smashing his foot, he hits it the first time and it shows a close up. If you watch the small amount of blood when he hits it again they have used the same shot. (00:04:00)
Revealing mistake: When the shark first attacks and bites off Jim's arm, you can briefly see his real arm under his shirt as he's screaming in pain. (00:34:10)
Factual error: When Janet Leigh is shown lying dead on the floor of the shower, there is a close-up of her open eye. The pupil is contracted to a pinpoint (obviously due to the bright lighting) where it should have been dilated. After the film was released, Hitchcock heard from several ophthalmologists who pointed this out and suggested he use belladonna eye drops in the eyes of "dead" people in future films, as the chemical prevents the pupils from contracting. (00:48:30)
Continuity mistake: When John is driving to work and he hears Anna on the radio, he swerves to avoid a car. From inside the car you can see that there are no cars in the rear window, yet when the shot changes to an outside shot, there are 3 cars. (00:33:35)
Visible crew/equipment: In the scene after Patrick Bateman's second encounter with the detective in his office, we see Bateman having sex at Courtney's apartment. After he rolls off her, Bateman approaches the large, stand-up mirror in the bedroom. In the upper right hand corner of the mirror, a boom microphone can clearly be seen moving around to pick up Christian Bale's lines. The next time we get the same long shot, the microphone is gone. (00:52:45)
Continuity mistake: When the old car blows up both of the dead zombies are gone. (00:21:40)
Other mistake: When Laurie has her episode in the bathroom about killing Annie, the clock stays at 7:03 the whole time.
Visible crew/equipment: Before Lorna has her throat slashed, you can see a tube pumping the blood.
Other mistake: Whenever Helen Hyde turns back into Richard Jacks, none of the clothes ever seems to rip or stretch - they both have different body types.
Continuity mistake: When Scott gets his throat cut, blood pours out. Yet when Terri spins him around, there's no blood anywhere on him except a small amount on his shirt sleeves.
Factual error: Budapest didn't exist in 1489. The cities of Buda and Pest weren't combined until 1873.
Continuity mistake: In the 1978 flashback scene, Michael does not have 6 bullet wounds in his chest from when Dr. Loomis shot him moments earlier.
Continuity mistake: Saw VII takes place straight after Saw VI. In Saw VI we see Jill put Hoffman in the bear trap and leave. We then see that Hoffman spends around 45 seconds trying to get the trap off before putting in the bars on the window. In this film however, just after Jill closes the door we see the glass break. No delay. (00:08:20)
Other mistake: When they encounter the first ant, the policeman runs out of ammo, but the FBI agent fires at least nine shots. Not bad for a snubnose revolver that holds 5 or 6 rounds.
Visible crew/equipment: When Marcus attacks Simon at the loading dock, as Simon flies through the air after Marcus kicks him, you can see the face of Johnny Lee Miller's stunt double. (00:57:15)
Other mistake: When Sugimura is looking for Kotohiki, he activates his scanner to see if she is nearby. The scanner shows her location, but fails to show either Mitsuko or Kiriyama, who show up quickly after.
Revealing mistake: As the Predator tends to his wounded leg, one of his claws can be seen bending as if made of rubber.
Plot hole: In the end of the film it is heard the police want to exhume the body of Charles Lee Ray from his grave site in New Jersey. Now when Chucky and the crew get to the grave site they find and kill a coroner who is digging up the body. He is the only one there at 1am, by himself, a lonely coroner without any police officers, after all this is a police investigation and I doubt the cops would have him there alone. Then right at the end the Detective who is hunting them arrives. Now he is a cop from Lockport, about six states away. A. Why did he drive all that way to see the body? B. A cop from all the way down there shows up but no new Jersey cops are at the scene?
Plot hole: So he needed the help of a big strong burly guy to flip the safe with the body, end over end to the pit, but he somehow was able to easily get it out of his basement and into the back of his car by himself?
Continuity mistake: Throughout the film Elvira wears her trademark black dress, split to the top of her thigh, and underneath it she always wears black pantyhose. Inexplicably, this changes to black stockings and suspenders when she is undressing for bed on her first night in her new house. (00:31:35)