Plot hole: It has already been mentioned that a certain shot reveals that Sidney isn't wearing the bullet-proof vest when she should be. Further to this, most of the shots in the climax sequence make it impossible for her to be wearing one, as you can see the contours of her chest throughout. A bullet-proof vest would flatten the appearance of this.
Continuity mistake: Gale and the killer go flying through the basement door, you see the door opens out, but when they crash through it, it opens in. Its not a two way swinging door, because you see the hinge at the top of the door to open it out, not in.
Continuity mistake: In Scream 2 Dewey walks with a limp and his right arm curled up. In Scream 3 he walks with a limp and his left arm curled up.
Continuity mistake: The ice pick remains free of blood even when Sid has stabbed the killer with it twice.
Continuity mistake: Gale's bangs change lengths throughout the film.
Continuity mistake: In the scene where Jennifer gets killed and falls through the mirror look at Dewey's hair it's all messed up, but in the scene right after that when Dewey and Gale are looking for Tyson his hair's all combed back again.
Audio problem: When the killer has on his mask and you hear "the voice," he does not need to use the changer to mask his voice. But we see that it is just a plain old Halloween mask.
Continuity mistake: Dewey rolls down a hill after shooting at the killer. The cut on his forehead changes shape from circular to two parallel lines then to a straight line and a waved one.
Continuity mistake: Roman's sideburns change lengths towards the end of the movie.
Other mistake: Cotton's opening line in the movie is that he won't go below 1 million bucks as he's risking his reputation for the cameo, furious that they can't write him a decent part for the Stab movie. So he's still negotiating, but the news story later in the movie says he filmed the cameo the day before.
Continuity mistake: At the end of the movie when Sidney is lying on the floor, Roman is pointing the gun to her head about to kill her. The gun is clearly pointing to her head/neck area when he shoots, but Sidney still lives and shows him she was wearing the vest. The vest protects her chest and Roman shot her in the head.
Other mistake: June 28 was a Monday in 1999. Jenny McCarthy was killed the day before, so on a Sunday. The scene takes places the evening (there's sunlight when it begins) after the night scene with Sidney; it is however uncertain if it is actually supposed to be the same day, or the day before, a Saturday. Therefore, Cotton, murdered a day earlier, was killed on either a Friday or a Saturday, but when he was killed there was a promo on TV about "tomorrow's" episode of his talk show, which is on during weekdays and so wouldn't be on for the weekend.
Other mistake: You can read the date of the event at Jennifer's house on the fax; it's June 28 1999. However, if you look at the director's office in the scene with Sarah, June was a very light month with according to the post-its mostly scouting for locations and such, and no shoots were scheduled in that month, as opposed to August that is full of those. All the previous scenes at the studio involved the actors on set for their scenes, and the news voiceover says that Cotton shot his cameo role the day he was killed.
Revealing mistake: When the house blows up and Dewey, Gale and Jennifer jump off the balcony, we find that Gale is near the car, the killer jumps up behind her. Dewy takes a shot at him with a gun and it is obvious that the killer awkwardly slams himself against the car window, rather than being caused by the impact of the bullet.
Suggested correction: Actually he would have to fake it because it is obvious, and later found out that he has a bulletproof vest on. if he wouldn't have faked it, everybody would've known that he had one on.
He faked really badly that being shot sent him smashing against a car, to avoid being suspected of wearing a bulletproof vest? How does that work? Dewey in the dialogue thinks he didn't even hit him.
Yeah, I'm with Sammo here. I don't really get the logic of the correction. I think it is just really awkward blocking/choreography/camera placement, and I do think the original mistake probably stands as-is.
