Continuity mistake: After Megan dies, for real, Jessica tells the others that they loved Megan and Megan loved them. Her robe opens and closes between alternate shots.
Continuity mistake: A spirit knocks Christine over and gives her a bloody lip. Her boyfriend tends to her lip, which is very swollen. As she sleeps, there is a close up of a fly going into her mouth between her lips that are not swollen at all. After she swallows the fly, she sits up and her bottom lip is swollen again. (00:37:05)
Character mistake: When Bower is banging on Payton's hyper sleep chamber from the outside it says Payton, but when it cuts to looking from inside out, it says Bower.
Revealing mistake: During crash scenes towards the end the local traffic in the background is driving on the left hand side of the road (filmed at Darling Point, Wynnum, Australia) even though the movie is set in the USA.
Continuity mistake: At the start of the movie Dylan Walsh cuts himself shaving and patches it with a piece of tissue, on the side of his jaw. Moments later as he's walking through the house the cut has moved to the corner of his mouth. (00:01:40 - 00:03:35)
Continuity mistake: Throughout the scene where the SUV crashes in the woods, Sadie is wearing large dangling earrings. In one quick shot where she is seen sitting in the back of the vehicle after the crash, her left earring is missing. It reappears in the next shot.
Continuity mistake: In the beginning during the cheerleader show the cheerleader to the right of Jennifer have her left leg stretched right, covering her right knee which is also somewhat turned right, in the next shoot, supposed to be just a change of the point of view, the same cheerleader have her left leg now straight to the left.
Continuity mistake: Near the end of the film, when Elsa and Clive are burning Dren's things, Elsa finds some drawings that Dren did of her. When she first pick up the pile, there are four drawings in her hands. When the camera pans out, instantly there are several more.
Plot hole: At the beginning there is an audio recording of Thomas talking to the police. He explicitly says 'They killed her! They Killed my sister, my mom!' or something to that effect and that Thomas was arrested for the rape and murder of his sister and he killed himself in custody. At the end, his sister is killed and the little epilogue says that the sister's body was found in her brother's arms and when their mother found out about the 'death of her children' she killed herself. That doesn't make sense logically. Thomas was alive when his mother was dead, according to the clip at the beginning.
Factual error: The scene where Princess and Steven are in Chrome Skull's truck, they are trying to dial 911. They are denied access because the phone is password protected. This would never happen. Even though there is a lock on the phone, it would be automatically deactivated for 911 calls. When you lock your cell phone to protect it from unwanted usage, the phone will deny all usage EXCEPT 911 calls.
Continuity mistake: Approximately 10 minutes into the movie the main character is going to burglarize a house and there is a guard dog on a chain in the yard that bites him, through a black mask, on his left cheek. After he is in the upstairs bedroom trying to open a safe, you can see blood around the hole near his left eye, but when he pulls off the mask, there is no longer blood on his left cheek, or any signs of a puncture wound.
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)
Factual error: The credits list several of the characters as "Arab." But the film is set in Afghanistan and the Afghans are not Arabs.
Revealing mistake: After the 4 have been tied up and babyface has killed their captors, he grabs Alexa by the neck. There is a shot of him from behind and you can see the make up covering the back of his head/neck coming up above his collar.
Continuity mistake: During the sex scene between Alex Pettyfer and April Pearson, April Pearson is not wearing a shirt. However, as Alex Pettyfer is dragged out of the car, she is suddenly wearing her shirt again.
Revealing mistake: When the girl is giving the guy a blow job in the school restroom, he finishes in her mouth. She goes to the sink and spits it out. You can obviously tell she had a mouthful of water going by the color and quantity. (00:20:45)
Continuity mistake: When she gets the pizza from the guy at the door, it is in a white box. When she goes in and sets it on the counter, it is in a brown pizza box. Then later, when she is running away covered in blood, she grabs the knife on top of the pizza box, and it is white again.
Continuity mistake: In part 2, as it shows the police cleaning up the crime scene from the end of The Final Chapter, they are shown picking up Jason's hockey mask to place it in an evidence bag. However the cut in the top of the mask from where he was hit with an axe in the previous film is missing. (00:01:05)
Character mistake: At the hospital, the inspector manages to get from the nurse the file of the patient with the liver condition. Forgetting the fact that the Turin, Italy hospital is using English for its documents (it's simply a cinematic convention), the problem is that the letterhead of this document says "Department of Chronic Deseases", misspelling the word.
Revealing mistake: When Steven Seagal makes his triumphant entrance in the credits, his sword misses the first zombie he supposedly hacks (right after "Written by"), by a mile. (00:03:20)