Continuity mistake: At the very end, when Sid finds out who the killers are, they are all standing in the kitchen. When Billy and Stu stab each other take a look at the blood stain on the left side of Stu's jumper. It starts around his shoulder and vertically goes down towards his waist. When Sid is fighting him in the lounge she gets up and goes behind the TV. In the shot looking straight down on Stu from a birds eye view, notice the blood stain is now horizontally across his stomach. You'll have to look closely for this one.
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: The Halloween scenes in the movie don't match up. For example, Randy is watching the part where JLC first discovers the bodies. About ten movie minutes later in Halloween, she's hiding from Michael Myers in the closet. Then Billy gets the idea to search for Sidney, because that's the scene currently playing. Too much time occurs between scenes for this to occur.
Visible crew/equipment: Look closely (you may need widescreen to see it) at the railing when Sidney is walking up the stairs outside in her parent's wooden patio talking to Tatum on the phone. You'll notice a quick boom shadow on the right of the camera as it's backing up. [Noticed also by Wes Craven on the DVD commentary track]. (00:22:25)
Continuity mistake: When Casey is making popcorn, firstly the top of the popcorn that she tears off and places next to the stove changes from being folded in half, to later on laying down flat. Secondly Casey picks up a salt shaker and places it by the stove, but this later disappears. (00:01:25 - 00:03:30)
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)
Other mistake: In the first scene with Randy telling Jamie Lee Curtis to turn around, the reflection in the TV never mirrors the actual position of Jamie Kennedy. (01:22:30)
Audio problem: Gale exits the TV truck telling her cameraman "I'll be right back" to go with the theme of the movie. However, the line is dubbed over and Courteney Cox says something shorter and different. (01:14:25)
Continuity mistake: When Dewey and Gale enter the house party Dewey jokingly takes a bottle of beer off a party goer then gives him it back. The bottle is back in Dewey's hand again when he speaks to Tatum. (01:03:40)
Revealing mistake: When Sidney is attacked by the killer for the first time (in her house), she is knocked to the floor and you can see she is played by a stunt double. (00:28:39)
Continuity mistake: After Casey has been stabbed in the chest she falls down and the killer gets on top of her, before he can stab her again she knocks the knife out of his hand and the killer instead starts to strangle her. She then kicks him off her but you can see he still has the knife in one of his hands as he falls backwards. (00:11:00)
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)
Audio problem: At the party, Gale places a portable small camera on top of the TV to spy on the teens there. Later, the teens are watching the Halloween movie on this very TV and talking loudly. The movie is playing with sound when they are watching it. However, when we see Gale and Kenny's perspective as they are watching the feedback, they can hear the teens talking. However, despite the camera sitting right on top of the TV, it doesn't pick up the audio from the movie playingr. This mistake is repeated not long after when Ghostface is sneaking up behind the one teen left behind on the couch who's watching the movie at an even louder volume.
Audio problem: After Sidney and Billy have their fight in the hallway after he's released, the scene cuts to Mr. Himbry reprimanding two students wearing the Ghostface mask. He takes some scissors and starts to cut them up and waves the scissors around. The entire time, the scissors are making very loud, very distracting and unrealistic "SHING" sounds like metal swords sliding against each other in a hallway. These scissors simply would not make such obnoxious sounds with the simple movements he's doing with them. They even make the sound as he's cutting through the mask, which if anything would have muffled the sounds they made even more. (00:44:50)
Continuity mistake: After the girl's dad leaves the room, Billy holds up a red stuffed bear against the bed. In this shot, the bear is only half sticking up at about its arm level, but in the next cut, it's high enough its feet are visible on the bed. Then only a second later as Billy starts to stand up, a jump cut has his arms go from down to outstretched with the bear instantly as he starts to stand. (00:14:10)
Continuity mistake: When Tatum calls Sidney at 7:15, she reaches over to get the phone. The sleeve is at her elbow in one camera angle, but it's instantly at her wrist in the shots before and after. (00:25:15)
Continuity mistake: When Sidney is in the bathroom at school, the trash on the floor around the trashcan changes. (00:45:25)
Continuity mistake: At the beginning of the film, Casey is cooking popcorn on the stove. When she peels the top off, you see her peel the side away from the handle, and she's using her left hand, but when the shot changes, she's using her right hand, and is pulling from the other side. (00:01:15)
Factual error: During the scene where the group of friends is watching Halloween, one boy says something like "Why do they do that? The blood is all wrong. It's too red." The problem is, during that part of the movie, no blood is shown or even implied. Bob is just pinned against the wall. (01:12:25)
Visible crew/equipment: There is camera equipment reflected in the door window when leaving the police station. (00:36:10)
