Scream 2 (1997) - 8 major mistakes

Visible crew/equipment: If you look really close in the background as the killer throws Cici off the balcony, you can see someone sitting in a tree, wearing black, with a camera.

Revealing: Just before the cop gets impaled through the head by the pole, you can see that it is obviously a dummy.

Factual error: If the glass in the cop car is weak enough for the killer to smash it without hurting his hand, shouldn't it be weak enough to break when he throws the cop against another window hard enough to draw blood?

Continuity: When Sidney and her friend get into the police car to be taken to protection, Sidney sits on the driver's side. When the car crashes, she is on the passenger side.

Revealing: In the opening scene when Phil gets stabbed in the head, watch carefully and you can see the retractable blade popping back out when he pulls his head away.

Continuity: When the Sheriff writes "Cici Cooper" on the chalkboard, between the closeup and wideshot of him writing, the handwriting and location of his writing dramatically changes, and the words "Maureen Evans" and "Phil Stevens" above, also change too.

Revealing: When the killer attacks Sid's bodyguards, the younger one has blood on his throat before the killer slashes it.

Audio problem: When Dewey is being stabbed up against the soundproof glass, you see a shot of Gail shouting "No." You can see a reflection of the killer in the glass standing motionless, but you can hear Dewey being stabbed.