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: The pipe bomb that Maggie uses to kill Freddy is the same one that was found in Spencer's room earlier in the film. It's already been established that Freddy was erasing the people he's been killing from existence, so that pipe bomb wouldn't be there to use on Freddy.
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: When the fat guy throws a boot into the ice-spray room, it freezes and shatters on the ground. You can see the length of the shoelace on the ground as well. The shot cuts to the guy in the shaft, and he pulls up the shoelace to reveal the end encased in ice, while the end is halfway into the ice block. This wouldn't be possible, because the other end of the shoelace had no ice at all, and there's no sign either of it breaking.
Plot hole: When Miss Scarlet tells the other guests, they can pay her in government information, she forgets Mrs White is the only to have no connection to the government and thus can't pay her that way, nor does she have any more money like the others.
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: It seems unlikely any mental institution would let a patient out to visit home for any length of time as happens in the movie with the killer and his mother.
Suggested correction: Unlikely, but still possible. Almost every workplace has a situation in which a person is bending the rules.
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: In the first film, the shape of the ring was a little different and it was set in a ring. Also, it was given to Xania. In the second film, she was never even acknowledged as donating it to the museum.
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: 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: The female employee says he's going to inherit everything, he gets it all. No he only gets 51%, the 7 dwarfs still make many decisions. (00:10:37)
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).
Plot hole: The Thorwalds were supposed to be in the apartment for only six months according to the lease, their phone number wouldn't have been published in the phone book for such a short lease.