Continuity mistake: Finding out that the gun is gone, Stu whines "Houston, we've got a problem here." Sid in background turns towards him instantly, but she re-turns in the next shot. (01:36:35)
Factual error: Gale Weathers points the gun at Billy and tries to shoot him, but the trigger doesn't pull back. This is explained by Billy when he says that the safety was on. Fine. But that gun is a Beretta 92F, and on a Beretta 92F when the safety is on, the trigger WILL pull back, but no round will fire. (01:37:20)
Continuity mistake: Gale falls back on the unconscious Dewey after Billy kicks her. Her jacket is draped across the chest touching the white button of her vest. When Billy gets on his knees by her though, the jacket is fully open. (01:37:30)
Continuity mistake: Stu is slumping against the desk and says he's dying. In the closer angles you can see his left fingers are coated in blood, but in wider angles (for instance when Billy grabs the receiver off him and yells "I'm gonna rip you up, you b**ch"), the fingers are cleaner. (01:38:40)
Continuity mistake: When Stu & Billy are in the kitchen after Sydney has escaped them, she calls Stu's house phone. Billy gets pissed and throws the receiver at Stu. It bounces off him and lands on the floor, yet when Stu picks up the receiver to talk to Sydney, it's on the table. (01:39:05)
Suggested correction: To be fair, Stu is shown having a grip on the phone's cord, and he had all the time to jerk it up on the desk overshooting his resting arm while he was off-camera during Billy's temper tantrum. Of course, it's also a known fact that Stu being hit and Matthew Lillard's reaction was an ad-lib kept in the final movie, so they were going to keep that take in the movie regardless - it might be a mistake, after all.
Revealing mistake: When Sidney in Ghostface costume stabs Billy with the umbrella, you can see the squared shape of a protection pad under Skeet Ulrich's shirt (which she misses the second time around, famously prompting a genuine scream of pain from the actor). (01:39:55)
Revealing mistake: After Billy's stabbing, Stu charges Sidney projecting her through a doorway. In that shot you can easily see that Matthew Lillard is replaced by a stuntman. (01:40:15)
Revealing mistake: When Sidney and Stu are fighting in the living room and they both trip over the couch, Stu's stunt double is visible and wearing a wig. (01:40:25)
Continuity mistake: At the end of the movie when Stu and Sidney begin tumbling (right before he gets killed) there is a bench in the background with a bag of ruffle potato chips facing upwards, in the next shot it is lying down. (01:40:30)
Suggested correction: There are three bags of potato chips; rewatching the scene, does not seem to me any of them changes position or orientation except maybe the leftmost smallest one that turns flat on the back instead of showing the green strip. The change though happens as the camera is away for two cuts on Neve Campbell first, then on Matthew Lillard as they're struggling, which would reasonably affect the flimsy foil bag.
Continuity mistake: When Sidney bites Stu's hand, in close-up the wrist is well visible and displays the bracelet in full, but in the wider angle that section is entirely covered by the bloody sleeve. (01:40:35)
Continuity mistake: At the party at Stu's house, when Dep. Dewey is walking through the house looking for the killer, Dewey walks into the living room with the TV and couch. Look at the TV, there is a white phone sitting right next to it. Later, when Sydney and Stu are fighting and she is about to push the TV on top of him, the white phone is gone. The TV also appears to be bigger. (01:40:40)
Continuity mistake: In the close-up with Sid smashing the vase on Stu's head, her arm is bloodied all the way down to the elbow, while when she reached for the object the blood reached just about the wristwatch. (01:40:40)
Continuity mistake: When Billy jumps on Sidney in the corridor making his comeback, a bag of potato chips that was lying against the bench's armrest goes from vertical to horizontal. It wouldn't be surprising that a small and possibly mostly empty bag would be toppled over considering the movement that just occurred, however when Sidney headshots Zombie Billy the bag is back being vertical. (01:41:20 - 01:42:30)
Revealing mistake: When Sidney sticks her finger in the wound made when Sidney stabbed Billy with the umbrella, Skeet Ulriches skin pad visibly does not connect with his neck. (01:41:30)
Continuity mistake: In the final scene where Sidney gives the "coup de grace" to Billy shooting him in the head after he suddenly woke up, he holds the left arm above the mask on his top left, but when he dies, his arm is lowered and the knife appears from nowhere. (01:42:30)
Visible crew/equipment: At the end when Sidney's dad falls out of the closet, if you look closely you can see the hands of a crewmember who was in there too, pushing items out after him. (01:42:40)
Plot hole: Given the magnitude of the crimes that occur at the house at the end, the police can be seen in the last shot dusting Dewey's truck. If the police are so careful as to dust for prints when the entire rest of the crime scene is heavily contaminated by everyone from the EMTs, Gale doing her news, police, etc. makes what they are doing seem silly. (01:43:25)
Factual error: At the end when they are loading Dewey into the ambulance on the stretcher, it is standard procedure to put the patient neck brace when they receive any type of unknown injuries (stab wounds) to their back as Dewey did - it was notably absent.
Revealing mistake: After Gale backs the van up, and Kenny's body falls on the windshield, they cut to a shot where Gale is driving away, and Kenny's body is on the roof of the van. When she starts driving you can clearly see Kenny lift his head into the air to look forward, even though he's dead.
Continuity mistake: Pay attention to the scene where Randy gets the call that the principal is dead and the rest of the group races off to try to see the body before they cut it down. Five or so people get up and run towards the door. When they are shown in the exterior shot running from the house to the car it is an entirely different group that are not even dressed similarly. This was due to the fact that the group were made up of actors whose contracts were by the week. The exterior shot was the only thing they didn't get during that initial week and to bring them back for that one shot they would have had to have been paid for an entire new week, which was too expensive for one shot. They just used extras instead.
