Plot hole: When Bridgette ran through the glass and Linda and Jim were at the hospital Jim tells Linda he called her mom and told her what happened and she was coming to stay over the next day. Yet apparently her mom forgot what happened because she had her committed because Linda didn't remember what happened to Bridgette's face. Also, Bridgette was like 9. How come no-one just asked her what happened?
Factual error: At the climax of the movie, Alice swings the machete at Mrs. Voorhees and decapitates her. When the blade makes contact with Mrs. Voorhees' neck, her head flies off at an incorrect angle, as though the cut began on the opposite side.
Continuity mistake: When Norma and Helen are in the salon, and they are talking about Carrie going to the prom with Tommy, Norma is getting a fancy hairdo done for the prom. But in the next gym scene, she has her plain braids and a cap on. (00:48:20)
Suggested correction: When you watch the movie leading up to that event, it's obvious that Norma is a tomboy, and is always wearing a ball cap and wearing her hair like that. It's who she is and perhaps decided after her hair was done that it didn't feel right and decided to go back to her look.
Factual error: When they go into the water, they put mouthpieces in, but, a few times, they talk to each other, which is impossible with mouthpieces in.
Suggested correction: Sorry to burst your bubble here but there is scuba equipment which allows for talking whilst using a regulator.
They're not wearing such equipment. In the movie they're just wearing regular mouthpieces.
In the DVD commentary the writers explain that the divers should have been wearing full face masks which allow for communication, but the director changed it for mouthpieces, but kept the talking in. They pointed out this mistake.
Revealing mistake: When Loomis shoots the marshal's window out, when he makes a u-turn you can see the tire marks on the road and dirt from previous takes.
Continuity mistake: During the paper cut scene, when Bella is thrown against the table, there are 5 vases of flowers and 3 sets of candles. After she hits the table she lands against one of the vases and knocks the 2nd one to the floor, but the next shot shows only one vase left upright. (00:14:50)
Continuity mistake: When Hauser picks up the Admiral, after the Brain Bug attacks them, she has no yellow alien blood on her as she's being pulled up, but when the shot changes, as she's standing up, she now has blood on her face and uniform.
Plot hole: Peter goes into Carl's mind to save Catherine. When he's in there he sees the tank with the water nymph. On the tank are strange symbols which provide the FBI with the clue needed to find the latest victim. Makes sense so far. But, go back to the scene just after the FBI have captured the comatose killer and are looking in his basement. The FBI are looking at the contraption that the killer uses to suspend himself over the victim. On the contraption is the same symbol seen later on the water nymph's tank. Why didn't the FBI follow up the symbol then?
Factual error: The moon is full every night the highschoolers are at the lake house.
Character mistake: When Lisa is taken to the hospital, she tells Kathy that she saw the ghost of Jodie DeFeo. The name of both of the DeFeo's daughters wasn't Jodie. Their names were Dawn and Allison. Jodie was the name of a demonic pig that the Lutz's daughter Missy had befriended.
Suggested correction: While this is true in the original novel, the writers chose to change it to the DeFeo's daughter's name in the movie. Creative license doesn't count as a mistake.
Continuity mistake: When the white boy is standing outside the car talking to the gangbanger inside the car, the gangster's sunglasses disappear depending on the camera angle.
Factual error: After Dr. Derry's hand is crushed by Calvin, it dangles and flops every time it is seen so that the audience can see that the bones are severely broken. However, in zero-g, the hand would float rather than swing limply.
Revealing mistake: When Henry's mom is pushed off the cliff her cable is visible.
Continuity mistake: When Christine is fixing herself after the guys smashed her up, her front end is shown to be perfectly straight for its entire width and the hood is missing. Near the end of the scene, the front end is shown crushed and unfolds again, and the hood appears from nowhere.
Factual error: During the plane ride into France, the Paratroopers are holding/carrying their weapons by their sides. In reality, their weapons (M1 Garands, B.A.R.s, etc.) would be carried in special "bags" strapped to their parachute harness. This not only protected their weapons, but also secured them to their person.
Continuity mistake: When Gwen and the police are at the house containing the buried bodies of the victims while Finn and the Grabber are fighting, the Grabber's van is not in the carport. However, when Finn exits the house, and he and Gwen embrace, it is. (01:28:03 - 01:34:27)
Visible crew/equipment: As Rick and Chris get in the Volkswagen Bug after Shelly returns it, you can see three crew members in the backseat window reflection. (00:35:55)
Other mistake: In the scene where Jamie is in the closet, looking at a photo of her mother (Jamie Lee Curtis). The photo looks exactly like the scene where Laurie is sitting waiting for Annie on the ledge in the original Halloween, which wasn't photographed at the time, it's clearly a still from the movie.
Revealing mistake: Throughout the film, the base station radio is not connected to an antenna. In many lengthy shots of the back of the radio we can see the power cord trailing out the back of the unit, but there is nothing plugged in to the antenna socket. This is especially annoying because base station radio problems are a key plot point.
Factual error: The type of surgery shown made by the machine transversely cuts the rectus abdominis muscles. Besides not being a standard surgical incision in order to "remove a foreign body" as stated, it seriously damages important muscles of the abdominal wall making any immediate active mobilization of the trunk virtually impossible, even under strong analgesia.