Plot hole: Peyton had his face burned in the explosion. In fact, he basically lost his lips, so he should not be able to talk very easily. While he could probably learn to speak normally again through other movements with his mouth and tongue, he does so too quickly to make logical sense. And his uncanny ability to almost perfectly mimic his enemies could probably be learned over time, but again is too quick to make sense.
Plot hole: When the cop is in the room and he realises how the teacher escaped from the hotel, he pictures him walking out in the bellboy uniform while the cop is downstairs. However at this time he should be upstairs with the girl in her room, because he is still in the room when she runs out of the room into the cop. For this to work out, the teacher would have to have left the room before the girl even got there.
Plot hole: In the makeshift morgue when Simon and Matthew first fight the vampires, Solina is shot and pinned to the wall with a large silver nail and remains calm and unaffected. However, moments later Marcus is fighting with Simon and grabs one of same kind of nails but must drop it when it burns his hands. It makes no sense that Solina had no adverse reaction to the nails at all when Marcus reacted so violently. (00:42:00 - 00:57:50)
Plot hole: When the policeman asks Kirsty at the beginning who came when she solved the box she says the Cenobites; she had no way of knowing what they were called. Frank only told Julia; Kirsty didn't hear it anywhere and the Cenobites themselves didn't tell her either.
Plot hole: The Hellworld website at the beginning of the film has eerie music and also Pinhead's voice reciting some of his famous lines from other Hellraiser movies, which is impossible; there's no way that someone could have gotten recordings of those moments in the past where he said the lines, so they couldn't be playing on an internet webpage.
Plot hole: At the end of the movie where David and his friends are attempting to break into Steve's house, David has the door code and attempts to gain access once by using it. Steve then tells his wife and the kids to go hide upstairs and turn off all the lights so nobody will know where they are. Then Steve and his wife go to another part of the house, away from the front door. Then, we hear David and his friends using axes and a big log to try and break down the door, "before* Steve secures the door with household appliances later on. Why wouldn't David have just kept trying the code?
Suggested correction: The reason David can not keep trying the code, is because the door has a lock on the top, and one at the bottom (middle regular lock). That middle lock is able to respond to the key/pass-code system, but the top one is not. In order to get in the house, David would have to be able to enter the pin (which, yes he knows) but with the top lock still locked from the inside he can not get in. I am assuming there is a key slot on the outside where he would need a key, and also I'm sure the family doesn't bother locking the top half of the door as no one else knows the pin (so they thought). And I'm guessing that they never locked it during the day either, and only at night.
Plot hole: When Ripley goes to access the computer Mother, the entry door opens and closes with a hissing noise, a couple of minutes later you see Ash next to Ripley with a smile on his face. How did Ash manage to open the same door without it making the hissing sound? Ash could not have been in the room before Ripley came in - once Ripley has sat down at the console, it rotates on a 90 degree angle, this would have made it impossible for Ash to be hiding behind a desk or a computer console without being seen by Ripley. There are many doors on the ship that make the same hissing sound when the doors open, an obvious example is the infirmary door. And Ash couldn't have disabled the pneumatics of the door, because when Ripley exits the room, the hissing noise is heard again. (01:18:40 - 01:20:00)
Plot hole: In what appears to be at least an hour or so after curfew is put in effect, Challis goes to a liquor store. Even if he didn't know about the curfew, why would the liquor store still be open?
Plot hole: In the scene where Katrina is watching through Valek's eyes as he kills father Molina, Crow orders father Giteau to "find out where an old padre is missing". But Katrina never described father Molina, all she said was "He killed the priest". Crow could not have known the age of the man who was killed.
Plot hole: Referring to that blackout night. How come the group can actually film how they put all their cameras and stuff into its hide?
Plot hole: The psycho coed murders her lecherous professor (played by William Shatner) by pushing him out a window. In the very next scene, she's driving around with his body propped up in the passenger seat of her car. She weighed no more than 100 lbs., tops, and Shatner was easily at least 250 when this film was made. No way she could have dragged him to her car and lifted his dead weight into the seat, no matter how much adrenalin she was pumped with. Physically impossible.
Plot hole: Everybody jumps into the water and emerges on the submarine except for Natalie. They're wondering where she is when they notice a flare. They realise it's her, and they send a search party. She's hiding on a bus maybe one to two kilometres away from the water. Her going there makes no plausible sense. Makes no sense how she held her breath underwater longer than anybody that they didn't see her and why she would go in the opposite direction of the sub. It was done to prolong the scene. (01:09:00 - 01:18:00)
Plot hole: The book says the demon has to devour 5 souls in order for the abomination to return, but it only got 4 since David saved Mia's.
Suggested correction: In the extended version, we see Mia's soul isn't actually saved.
"In the extended version" has no relevance. Bonus content holds no weight when leveling criticism at the theatrical cut of a film.
Suggested correction: Actually, more than five souls were claimed over the course of the film, whether or not you count Mia. Four people died in the cabin, plus the possessed girl in the beginning of the film, in addition to the girl's mother, who is mentioned to have been killed by her. You could also make an argument that the dog counted, technically. You also gotta remember, the book said the souls must be "consumed," and technically, it did possess Mia and she "died" while still possessed before being revived. So by the vague definition of "consumed," she could still possibly count. Either way, definitely more than five souls were claimed over the course of the film.
Brother and friend were also technically cleansed by fire.
Plot hole: When John is painting the doll's face he looks down at a photo printout of Amanda, you will notice the bruising/scratches on the side of her face in the picture. Please take note of her hair, shirt and overall demeanor. Now think back to the first Saw when Danny Glover had Amanda in the interview room. The picture that John Kramer is looking at is a picture taken of her in "that exact" interview, this is strange however considering that the interview took place after she escaped the jaw splinter, so how does John have a picture of her from the future? (00:51:40)
Plot hole: Hoffman is able to implicate Agent Strahm as the mastermind behind the main series of traps in this film by planting Strahm's cell phone at the scene. However, Hoffman is repeatedly shown to be touching things at the scene without wearing gloves, so a forensics sweep of the crime scene afterwards would show Hoffman's fingerprints all over the place and reveal him to be the actual mastermind. Agent Erickson arrives at the crime scene before the two survivors of the traps complete their tests, so the forensics team would have been called in before Hoffman had a chance to remove any evidence that would incriminate himself. As a forensics officer himself, Hoffman should know better.
Plot hole: It is highly unlikely that the murderer knew Phil was going to put his ear to the stall when he heard the babbling. It is even more unlikely that the murderer is going to get him on the first stab through the stall. (Which also requires a lot of strength). We also have to assume that he spent time hanging out in the bathroom knowing Phil would go there to begin with, and that other two men with weak bladders were doing the same simultaneously forcing the victim to go to the stall to begin with. (00:07:45)
Suggested correction: The killer is incoherently whispering in a strange way in the adjacent stall to lure Phil to press his ear up against it. After stabbing him through it, the killer inspects the knife inquisitively, as if checking to see if he actually got him. While it's still not a terribly plausible scene, the killer's demeanor suggests that he encountered Phil in the restroom by coincidence and improvised the kill, rather than anticipating all of Phil's actions as part of a perfectly executed plan.
The general logistics and planning of the murder are a separate issue - because no, the murder was planned. The entry just says that it's "highly unlikely", putting it mildly, that the killer could guess the exact position Phil would pick to listen to the noise. Just a few inches up or down, left or right, make a huge difference. The killer looks at the knife admiring the results, because if he had any doubts that he got his victim, he'd be trapped in a bathroom with a screaming, wounded, angry Phil and plenty people who could come and help.
To be more clear, the correction here is that Phil had heard strange talking/whispering rather than music, which makes it at least a little more plausible the killer would think he might put his head up against the wall at a certain spot. Unlikely for sure, but unlikely isn't a mistake, it's just what movies do. Phil's death was planned yes, though it stands to reason the plan was more "surveil and strike when vulnerable" and less "wait for him in this particular stall we know he'll be next to."
Plot hole: Despite being whipped and needing to go to the hospice afterwards to have her wounds seen to, when we see Madeleine later in the film she doesn't act as though she had whiplashes across her shoulders - she lies on her back that very night in bed, and gets up without a wince, she holds her shawl close when she is wandering around the asylum, she leans back against chairs, and in all the later scenes she is still wearing her tight bodice, despite the fact that such wounds would have been very painful for ages afterwards.
Plot hole: When Jason is going next door to chase after Trish, he pulls Jimbo's body down from the doorway and begins walking towards Trish's cabin. He is seen walking by himself. However in the next scene, he throws Rob's body through the window. There was no time for him to go back and get the body. (01:17:15)
Plot hole: When the innkeeper is asked by the rich ex-actress to give her the key to a nice room, he gives her a key telling her that eight is cozy and the key has an 8 on it as well. But a few minutes later, when this woman is about to be murdered, she leaves her room (holding her mobile phone) and the door has a 9 on it. How can a key to the room 8 open the door of the room 9? [Still a mistake, but there's an explanation. In the DVD extras you can see a deleted scene in which she changes rooms because she wasn't happy with 8.]