Revealing mistake: When Natalie is in the old building and she is looking around, she opens the door and Parker's dead body falls out onto the floor. When it cuts to a close up of his body, you can clearly see the side of his neck pulsating although he is dead. (01:19:50)
Continuity mistake: When Natalie opens the door and Parker's body falls out, it is covered in foam from the way in which he was killed earlier on. Between shots the foam covering his differs. Also, the position of his right arm changes between these shots. (01:19:50)
Revealing mistake: In the chase sequence, we get a shot of who is supposed to be "Brenda" driving, but we see the eye of a man, not a woman. Brenda doesn't have bushy eyebrows, and her eyes are a different shade of blue. (01:20:05 - 01:24:20)
Continuity mistake: Near the end of the movie Natalie finds Brenda laying on the bed. Then suddenly Brenda gets up and suprises Natalie by punching her on her right [our left] cheek. However when Natalie awakens, tied to the bed, the bruise is on her other cheek. (01:21:00)
Continuity mistake: Brenda is showing Natalie a slideshow using a projector to show her how her boyfriend was killed; she firstly shows a photo, then a newspaper article. The article is left projected for the whole scene. That is until Brenda is shot out of the window, and now it is the photo that is back to being projected. (01:22:20 - 01:28:45)
Continuity mistake: When Brenda is caught wounding Natalie by Reese, she backs away. As Reese points her gun at Brenda and tells her to back up, between shots Brenda's coat keeps changing it's position on her shoulders from on or off them. (01:26:15)
Continuity mistake: In the climax of the movie, Brenda is shot out of the boarded up window. However the boards that are nailed across the window change. Firstly, there are only a few planks with many gaps. But from outside, the whole window is boarded, with NO gaps. (01:28:40)
Audio problem: When Natalie shoots Brenda backwards, causing her to fly out of the window, we hear the sound of smashing glass as she flies out. However there was no glass; the window was missing and the hole was boarded up with planks, so we should not hear glass. (01:28:45)
Plot hole: During the end the murderer is thrown out the front window of the building. The students leave the building through the front door, but yet there is no body, and that doesn't seem to bother them!
Continuity mistake: At the end of the film, Paul went in the house when it was raining, but his coat is not wet.
Other mistake: The killer leaves the corpses of the Dean and Parker where they are and walks away, but they later appear in the room at Stanley Hall.
Suggested correction: That is because the killer is moving around the bodies. Just like when Damon is killed. His body is not where it was left when Alicia Witt comes back with the cops.
Continuity mistake: When the killer has hanged Damon in the tree and smashes the front window of the car, the girl in the car is backing, and when she does that the killer falls off the car, and then you can, if you listen carefully, hear a mans voice "say" something like "uff". The killer is a girl but the stuntman is a man.
Factual error: If you cover someone's mouth with a 2-3 inch strip of duct tape, or electricians tape, rather than go around the entire head, it is VERY VERY easy to repeated open your mouth wide, then scrunch face over and over again and work the tape off to the point where you can scream. Actually, duct tape, which is used by most of the offending movies is even easier than that. It can usually be almost completely removed in a matter of seconds. Electricians tape as used in this movie, is a little harder since it is stickier, by still can be done fairly easily. I suppose that it can be argued that people in these situations are scared, or don't know any better and therefore don't TRY to remove it. But in this movie, the main character is getting her stomach cut open and screaming in intense pain. This would cause enough facial movement for the tape to work itself free.
Plot hole: In one gruesome scene, the killer hangs Natalie's friend in the woods and then crashes a car into a tree. Natalie escapes and comes back with campus security (who didn't bother to call the police even though a murder had just been committed). When Natalie and the guard get to the murder scene, all evidence is gone. How did the killer manage to remove the body and all pieces of the car within ten minutes (not to mention somehow hide the dent left in the tree by the car crash)?
Plot hole: When Natalie and Damon are in the woods when Damon goes to the bathroom and the killer approaches him from the behind, it cuts to the scene with Natalie in the car. Then she gets out and sees the killer then runs to the car. You see the killer put rope on the car but how does the killer hang Damon without Natalie noticing?
Other mistake: Why would Natalie get probation? She wasn't driving. It wasn't even her idea.
Suggested correction: Lawyer here - Not a mistake at all. She would be liable as an accessory, under aiding and abetting. The exact crime varies between common law jurisdictions, but she is laughing along when Michelle is speeding and terrorizing the other driver. In common law jurisdictions, that would be viewed as encouragement of Michelle's committing a crime (she explicitly says she didn't tell Michelle to stop), which is a form of abetting, and indeed carries criminal charges.
Factual error: After Tosh got her wrists cut, she wasn't discovered til the next morning. After so long blood stops flowing from a wound so the blood from her wrists wouldn't soak through the sheet as seen.
Continuity mistake: At the end when Brenda flies through the windshield, she goes into the water face down. When Natalie and Paul see her floating, she's face up.
Revealing mistake: When the killer calls Parker, when we see the phone it's not showing details from caller ID, it's just showing the address book.
Visible crew/equipment: When Sasha falls from the stairs, you can see a safety wire.
