Continuity mistake: After Sidney slaps Gale on the face, Gale's hair changes its appearance / position between the two reaction shots. (00:24:25)
Hamster

Continuity mistake: When Sidney wakes up and answers the phone, the position of the watch on the desk, beside the caller ID, changes between shots. (00:11:50)
Hamster
Continuity mistake: When Cici is running away from the killer, when they reach the second floor of the sorority house the distance between them greatly increases between shots. (00:33:10)
Hamster
Continuity mistake: When the killer attacks Sidney and the bodyguards in the car, he smashes through the driver's side window, leaving some of the glass still around the edges. When the killer drives off, these fragments have dissapeared and the window is totally gone. (01:22:40)
Continuity mistake: In the opening scene - the premiere of Stab - when the girl is about to go back into the theater, you see the door into the theater. In the next clip, when she enters - the door is much wider.
Jacob La CourFactual error: At the end of the film there is an LA county sticker on the ambulance, but the events are nowhere near LA.
cameron daviesPlot hole: It is highly unlikely that the murderer knew Phil was going to put his ear to the stall when he heard music. It is even more unlikely that the murderer is going to get him on the first stab. (00:07:45)
Joel GordonContinuity mistake: During the scene where Gale is underlining the names with the connection to Woodsboro on the board, she underlines 'Stevens' with the camera behind her and the line reaches across the whole name. In the next shot, the underline is just reaching up to the 'n'. (00:41:40)
Continuity mistake: Shortly after the scene in which the killer pulls Randy into the van, Gale and Dewey run to the van and see the blood. Right before they open the door, there is a camera shot from inside the van through the window. You can see that the window is not broken: it is obvious that there is some sort of white fabric over it.
Continuity mistake: In the beginning of the movie, Jada Pinkett orders a popcorn and a small Pepsi from the concession stand. As she walks back in to the theatre she clearly has a jumbo sized large. (00:05:20)
Continuity mistake: The killer throws Cici off the balcony facing the ground. In the next shot of her falling, she's flipped over on her back.
amycamille1975Plot hole: After Sid and her friend get out of the car, they run away from it. Yet somehow while they are talking, the killer climbs out of the car and ends up behind them without them seeing a thing.
amycamille1975Continuity mistake: When Sidney is doing her theatre performance, when she lifts up her red veil she wraps it around her shoulders twice between shots. (00:55:20)
Hamster
Continuity mistake: When Debbie Salt is holding the knife on Sidney, the knife changes positions from time to time. (01:42:30)
Continuity mistake: When Dewey and Gale are in the classroom and as they are making out, when they realise that they are being filmed, Dewey has one side of his jacket off below his shoulder and in the other camera angle it shows that he has it perfectly on.
Revealing mistake: Towards the beginning, when Gale Weathers is talking to the sheriff who is standing at a podium, you see Mickey filming her with a hand-held camera. A panning shot going right following Mickey with some friends walking sideways reveals him looking at the camera twice. This is because he was waiting for his cue to stop.
Continuity mistake: In the beginning where Jada Pinkett Smith is stabbed in the back, you see a white girl to her right look down at her arm as Jada's blood lands on her. If you watch the background closely as Jad is dying and stumbling around, the same girl is still looking around, as if it just happened. (00:10:10)
Continuity mistake: When Gale is in the theatre and gets shot and falls from the stage, she has blood stain on her left breast (above the place where the shot wound appears). Yet later, when she climbs back to the stage, she has no blood stain, only the shot wound. (01:37:20 - 01:45:45)
Revealing mistake: At the start when Phil Stephens is being stabbed, when the killer draws back the knife you can see there is already blood on the knife. Its only there for a second so you have to look carefully. (00:07:45)
Other mistake: Maureen gets popcorn and a coke, yet doesn't pay for it. Nor does the cashier ask for money.
amycamille1975
Chosen answer: In real life, they'd have known there was a phone call involved. They would have known her boyfriend was killed. They could have easily pieced together that the killers played a cat and mouse game with the Drew Barrymore character. But that doesn't account for all the details. Anything else would be speculation. My speculation: Maybe Billy Loomis kept a diary.
K.C. Sierra