Scream 3 (2000) - 6 major mistakes

Continuity: In the scene where Gail and Dewey find the killer's voice changer, Gale's hands are clean, but when it shows her hands picking up the device, there's dried blood on them. But when it shows her hands again, the blood's gone.

Continuity: When the killer and Sydney are locked in the screen room together and the killer slits the movie producer's throat, if you watch closely when he's talking to Sydney and waving the knife around that in the first shot there's blood on the knife and then it goes to Sydney and back on the killer and when it cuts back there is no blood on the knife. It then again goes back to Sydney, then back to the killer and the blood has magically reappeared on the knife.

Continuity: After the killer chases down Tyson smashes him into the cabinet and throws him off the balcony you can see the black fabric of the mat fly up after the stunt double landed on it.

Continuity: When Sidney is fighting the killer, when ever a big stunt comes up, the killer's hair gets lighter.

Plot hole: It has already been mentioned that a certain shot reveals that Sydney 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.

Plot hole: How did Kincaid get a picture of Syd from the Delta Lambda Zeta party in part 2? No one took any pictures of her. Aside from that, anyone who's seen pictures of Neve Campbell online will know that that's a publicity shot from Scream 2 rather than something intended to be a "real" photo.