Other mistake: When the killer is stabbing Randy, you can see his reflection in the side mirrors. He stabs him many times. The same amount of blood is on the knife every time he lifts it up. (01:02:45)
Other mistake: When Gale and Dewey are being naughty in the VCR room, Gale spots some of the footage the killers took of the victims. One of the clips features Maureen and Phil in line in front of the cinema, but not only the shot is basically an impossible one since it's shot from a car and in the whole scene there were no cars in the street, but also the movements of the two actors are entirely different from the ones in the opening scene during that line about "a bio." (00:00:25 - 01:18:05)
Other mistake: Ghostface tries to kill Sidney by the front door of the sorority house, and the pendulum clock shows it's 12:10, which fits also the timeline with CiCi's murder. Running away from him though, Sid passes by a mantle in the party room that has a clock that strikes 10 to 7. (00:39:40)
Other mistake: The movie is supposed to happen "a couple years" after the previous (words of the moviegoer behind Jada Pinkett) but the current date shown at the theater says 1997, and Scream was set in September 1996 (calendar at Stu's house distinctly visible when he brings Sid's dad out of the closet).