Continuity mistake: When there are shots of the popcorn cooking on the stove, growing larger, in some shots there is a popcorn wrapper to the right of the stove, in others there isn't. Also Drew puts a silver salt pot down to the right of the stove, which has disappeared in later shots. (00:00:25)
Continuity mistake: When Drew goes to answer the door to the trick-or-treaters, the table to the left of the door has nothing on it. Yet when Drew sees the killer, a banana, grenade, knife and gun are now lined up on it. (00:02:15)
Continuity mistake: When Bobby and Cindy are in her room the first time and they're laying on the bed, in one scene it shows a TV next to her bed. The next shot it is gone. Then when Bobby starts to go out the window the TV appears again. (00:06:50)
Continuity mistake: When Buffy is getting out of her Dad's car and starts to walk over to Brenda and Cindy, she steps over a curb in the street. When the shot faces Brenda and Cindy, instantly Buffy approaches them and has already crossed that big street. (00:09:15)
Continuity mistake: Near the beginning Buffy tears off her dress and throws it on the ground. When they walk away there's no sign of it. (00:09:20)
Continuity mistake: After Heather is campaigning in the hallway of the school and giving out flyers, Buffy grabs the flyer and lets go of it, and is holding nothing. In the next scene where Buffy, Brenda and Cindy walk over to their boyfriends, Buffy all of a sudden has a folder, some books and a banana in one hand. (00:11:45)
Continuity mistake: In the scene after they look at Greg's report card, Ray has his hand on Brenda's ass, in the next angle it is on her shoulder. (00:12:05)
Continuity mistake: When Ray hands Bobby the tape to put on in the flashback it is in a case, however, Bobby puts it on without taking it out of the case. (00:14:10)
Continuity mistake: When the bottle is dropped in the car, it hits Cindy on the head and falls down in front of her. When Greg gets out he now has the bottle. (00:15:15)
Continuity mistake: When Greg stands up through the car's sun-roof, during the flashback, he is holding an empty bottle, but when he is at the top of the car the bottle is nearly full. (00:15:20)
Continuity mistake: When the six characters are imitating the scene of I Know What You Did Last Summer, they get out of the car after it has spun around. All of the headlights are on, the two yellow and the two white. Later, if you look behind them, the left headlight is off. (00:15:45)
Continuity mistake: In the scene where they hit the fisherman, they spin the car. Notice the yellow line, they are somewhat over it in one scene, then in the next the line in to the right of the car, not under it. (00:15:55)
Continuity mistake: When the gang hit the guy with the car they all get out. When Greg gets out he only has the bottle in his hand but when the camera returns he is holding a flashlight. (00:16:00)
Continuity mistake: In the flashback of the gang killing the fisherman, Shortie drives up in his car and just as someone says, "Brenda take care of them" there is a shot of the car with no smoke inside it. The camera cuts to a view of Brenda approaching and the car is full of smoke. (00:17:30)
Continuity mistake: After they dump the body in the water, Greg tries to get Cindy to agree to the pact. When she doesn't he starts strangling her. When he lets go, Cindy starts to reach her hands to her neck but in the very next shot her hands are at her sides. (00:19:35)
Continuity mistake: When Greg confronts Ray about the picture he found in the locker room, he shows them all and they start laughing. Buffy is on the left part of the screen, (on Cindy's right side), then Cindy explains that she got a note. Then when she says: "Somebody knows.", Buffy is more to the right (or left of the screen) than before. Then when Cindy says they have to call the police, Buffy's back to where she was at first. (00:26:50)
Continuity mistake: In the scene where the killer is in Cindy's house, the killer is hiding behind the couch. When you see shots of the killer, the cell phone is in his right hand and the hook is in his left. When she notices him and he stands up, the phone is in his left hand and the hook is in his right. (00:33:30)
Continuity mistake: When Cindy is running up the stairs and throwing the bicycle and piano at the killer the staircase is straight but when she goes to open the door and sees Doofy, if you look behind her the stairs are spiral. (00:34:30)
Continuity mistake: In the scene where Buffy and Cindy get dressed in the locker room, a girl standing right next to Buffy first drops her towel to get dressed and a few seconds later has the towel wrapped around again. (00:44:05)
Continuity mistake: When Ray is with Brenda in bed, and she get out, we can see her pillow in one form, and in the next scene is in another form. (00:49:20)
Chosen answer: I know for sure they were making fun of the movie 'Usual Suspects' (dropping the cup) - they might have added the gag of the fish in it to appear as though she was shocked by the fish instead of the true identity of Doofy.