Plot hole: Every ghost that we see in the house looks the way they did when they died, for example the girl from the film's intro is seen without skin on her face, which happened to her before she died. However, in the final scene when we see Simon's ghost joining them, he looks completely normal, when he should have had a throat slit wound and the carved markings on his skin. (01:31:20)
Plot hole: Holly's camera went back to 1959 with her, but her camera is inside the hatch with the same footage that the soldiers retrieved with her body.
Plot hole: The killer has been living in the (apparently big enough) crawlspace between walls and floors, for over a decade. There is no explanation (or rationale) given on how he moved the various objects inside every room, closed doors, fed when the house was not occupied, hid the various corpses and, silly detail, concealed his own BO and the stench of his own living quarters, which is something hinted at when they find out his hideout. It is explicitly said that he is agoraphobic and does not get out, ever.
Plot hole: For the murder on the highway to happen, the killer (who is not a mastermind, but someone who has a daily job and who never killed before) had to sabotage the car of the victim in such a clever way that he'd stop at a specific point and time (so, predicting also he'd escape out of town and do it through a certain route, which he had no way to predict), and that he'd react to the mechanical problem waving at passing cars walking in the middle (literally in the middle, not the side, or the emergency lane; perfectly in the middle of it) of a highway, where he can drive his semi into him - all while the fog is incredibly thick. Needless to say, it is all a bit too convenient.
Plot hole: Blore's death is fairly absurd, since the killer couldn't plan that he'd be standing, with all the possible room outside of the house, exactly in that spot at that distance from the window, with a ton of bricks that are precariously balanced on stone spheres that survived storms and heavy winds but somehow are loose enough to require a gentle push to fall down. (01:25:30)
Plot hole: It doesn't make sense for the prosecuting attorney to agree to accept a guilty plea from Danny for assaulting an officer, possession with intent to distribute, and resisting arrest with no accompanying guilty plea for at least a lesser-included offense of murder (such as voluntary manslaughter). A violent gang member committing an initiation murder while out on parole would be dealt with much more harshly, especially when the murder victim was a high-school-aged teenager and random victim. (00:09:34)
Plot hole: Derek, who escaped the mental hospital by pretending to be his twin brother Tyler, was able to locate Tyler's vehicle by using the keys to beep its horn. Once inside the SUV, he apparently found Tyler's cell phone, which is odd because most people carry their cell phones with them. But Derek did not ask Tyler for his cell phone's password before rendering him unconscious - so how did he gain access to the cell phone without the password? (It isn't likely that Tyler previously gave it to him). (00:20:40)
Suggested correction: Tyler never left his cell phone in the car. He had with him when visiting Derek. We see him pull out his cell phone to show Derek a picture, so the phone was already unlocked, assuming he locks it with a password in the first place.
I haven't had time to finish posting the rest of the mistakes I have, but I just uploaded two that should show up under "pending submissions." They probably should have been posted before the one above. I suppose the real question is where the cell phone came from each time.
Plot hole: Tony said, "If Danny beat him [Kevin] any more, he would have never lived" and Kevin spent a month recovering in the hospital. Tony and Danny were "advised to take a plea" and agreed to 10-25 years in prison. When Kevin went to the correctional facility to "forgive them in person", Kevin said, "We never properly met. I was in the hospital during your trial." Guilty pleas do not result in a trial and a felony criminal case would not be resolved within 30 days of the commission of the crime. (00:44:50 - 00:49:06)
Plot hole: When James leaves the resort after finding his passport, he packs his bags and boards a bus headed for the airport. The bus is then intercepted by Gabi and the gang, and James gets off, leaving his belongings on the bus. The following morning, when he proceeds to leave the resort a second time, he is shown packing his bags in his hotel room, despite having left them on the bus.
Suggested correction: We only see him get off the bus, the next shot is him walking with the cars behind him. They could have got his stuff from the bus in between shots.
Plot hole: The movie establishes that the FBI has a list of suspects thanks to security camera footage from the area where the victims were found. "A red headed man, two African Americans above average height, a white haired man." Then, the zinger; "a man in his 30s with a tattoo of a rabbit or an animal on his right arm", which of course is our guy Josh Hartnett. We see the tattoo, and it's a little doodle of a sheep, about a couple square inches big, below his wrist. That doesn't really make sense; if they have security footage with that level of detail, one wonders how could the rest be so vague. The next entry mentions "a male with a scar on his jaw", which is even more absurd. Either the security cameras picked those details up along with the suspect's full appearance and mugshot, or they just can't know with such certainty (if the suspect was masked or concealed in any way, then they would know for sure it was the killer and wouldn't be chasing people with wildly different appearances).
Suggested correction: I don't think you're wrong, but I think most of the FBI chief's voice was hallucinated. They shared the same voice; he was imagining her giving tips to the police, etc., etc.
Plot hole: When Holmes starts the human chess game, he says, 'Who had entered the lists, the king's pale knight.' This refers to moving the white knight of the king's side. However, the ritual does not mention to which square it should move. Still having three possible squares to move to (since the knight is on its initial square and the game has already started), Holmes knows and indicates that the knight (Dr. Sexton) must move to square F3.
Plot hole: Emily learned Italian during her youth in Rome, thanks to her time there and Dante Versano's tutoring. Considering that a good portion of the movie we don't deal with the real Emily but with another person impersonating her, it's unclear how this imposter could have learned the language and everything else about the family, given she certainly didn't have years to prepare and Emily's life as "Olivia" was not publicly known.
Plot hole: At the start of the film, the club are discussing Angela Hughes' murder, and they say they need another member of the club who has a medical background to answer some of their questions on the case. That's why they eventually ask Joyce those questions. But the club actually already has a retired doctor among their number. Ibrahim mentions he's a retired psychiatrist. Having a specialism in psychiatry doesn't change the fact he's a doctor, so he has the necessary medical background.