Continuity mistake: When Sidney answers the phone at the sorority, look at her sheer top under the jacket; reaches almost the neck (you can backtrack the moment when it rose from its optimal fit; she put the jacket in the same take and that ended up pulling the underneath garment a bit). At the next cut, the top rests lower as it should. (00:39:20)
Continuity mistake: Trying to kill Sidney, Ghostface plunges into the front door of Delta Lambda a knife that is soaked in blood - even if they already cleaned ACICI's. Derek on the other side of the door looks at a knife that is mostly clean except a couple of tiny specks by the blade, and Ghostface pulls the knife back again bloodstained. (00:39:40)
Continuity mistake: When Chief Hartley 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. (00:41:20)
Continuity mistake: During the scene where Gale is underlining the names with the connection to Woodsboro on the board, she underlines 'Stevens' with the camera behind her and the line reaches across the whole name. In the next shot, the underline is just reaching up to the 'n'. (00:41:40)
Continuity mistake: After the meeting with the police chief, Gale asks Dewey to let her help out. During their conversation, the natural light changes wildly depending on the angle; just look at the collar of David Arquette's jacket. (00:45:50)
Continuity mistake: During the Top Gun scene, Derek steps on the table where Portia De Rossi and the other sorority elites are having lunch. You see her fetch from the table the Pepsi can, but then she holds it at a different height at the cut. (00:48:15)
Continuity mistake: Derek gives Sidney his necklace and the two kiss. He puts his hand on her shoulder, then in the same shot the hand slides down, lower than the elbow. Wide shot, and he's still holding her shoulder. (00:50:00)
Continuity mistake: When Sidney is doing her theatre performance, when she lifts up her red veil she wraps it around her shoulders twice between shots. (00:55:20)
Continuity mistake: Sid is talking to Gus, the drama teacher who is adamant that it's a good idea to put her in a scene with half a dozen masked people play-stabbing her. She says "I'm a fighter", and behind her there are a couple girls making their way through the seats and a guy carrying a drink from the other side. Gus swiftly replies "I didn't hear that", and the camera cuts back to Sid, showing the people who were in transit a split second before already perfectly seated. (00:55:35)
Continuity mistake: Nobody moves after taking their masks off and looking at Sidney helpless on the floor. There's a close-up on two guys who take off their mask, one is a robust guy with short hair who removes a bearded old man mask. When Sidney flees, she passes by him, who is not standing close to the other guy anymore. (00:59:25)
Continuity mistake: When the cameraman says he's "one verb away from vacating these premises", there's a blonde with a green backpack walking left to right in the background. The same blonde appears two shots later behind Randy, who is further to the left than Joel. (01:01:45)
Continuity mistake: Gale, Dewey and Randy stand to go look for the killer who just phoned them. Throughout the earlier part of the scene the background behind David Arquette's close-ups showed the house and ground with a lot of sun filtering from the foliage, and the background behind Jamie Kennedy was much darker, but now you can see even the 'Arquette background' being dusky. (01:02:50)
Continuity mistake: The killer asks Randy what's his favourite scary movie; there's a POV of Randy that spots two girls sitting on the lawn. A tree behind them casts a big shadow in their direction, which changes orientation entirely in the shot when he touches the one with the phone. (01:03:10)
Continuity mistake: When Randy is jumpscared by the guy playing football (something the killer couldn't predict), in the aerial shot the football dude is standing on the crossroad that is fully in the shade instead of partially in the sun like before the cut. The two girls Randy harassed are also gone from their spot, which means in 5 seconds they packed their books and stuff they had laid out in front of them. (01:03:30)
Continuity mistake: Gale dispossesses a girl of her phone and starts arguing with the person on the other side. The girl has a friend to the left of the screen who just before Gale throws the phone back raises his hand. In the next shot his hand is on his knee. (01:03:45)
Continuity mistake: Shortly after the scene in which the killer pulls Randy into the van, Gale and Dewey run to the van and see the blood. Right before they open the door, there is a camera shot from inside the van through the window. You can see that the window is not broken: it is obvious that there is some sort of white fabric over it. (01:06:05)
Continuity mistake: When Cotton presses Sid against the library wall acting all creepy, Neve Campbell's hair is arranged differently on her forehead, sometimes with a stray wisp, sometimes not. (01:08:05)
Continuity mistake: At the police station, Cotton sarcastically says "Ok then, book me." Look at the door the chief of police is walking towards, which has his name on. In close-up there is a string touching the C of "Captain", that is missing in the wide angle. (01:10:10)
Continuity mistake: Once Gale tells Dewey "I feel bad, Dewey. I feel really bad!" and it cuts back to the previous camera angle, the sunlight behind her (where Joel's taxi is and then was) changes abruptly. (01:14:25)
Continuity mistake: Outside the police station, Dewey stops because Gale is being sympathetic with her 'feel bad' speech. His hand is on the corner of the public phone in one shot, to the left in a different spot in the next shot. (01:14:35)
Answer: His main motive was fame, or infamy for that matter.