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)
Visible crew/equipment: Hearing about what happened at Omega Beta Zeta, Derek tells Sidney "let's get you home" and when she gets inside the camera comes closer to Jerry O'Connell for a dramatic shot...that catches in frame part of the stage light. Actually spotted by Wes Craven during the DVD commentary track. (00:38:35)
Continuity mistake: When ACICI apologizes for calling the guy "Ted" and says "I thought you were someone else" she is suddenly touching her left cheek between shots. (00:30:00)
Continuity mistake: Cici wrongly assumes his ex is at the phone and says his name; "Ted?" The blue pillow she's leaning her right part of the body agains changes position between shots. (00:29:35)
Continuity mistake: Gale massages her chin after she's hit, but does it alternatively with her thumb tucked under the chin or outwards, depending on the camera angle. (00:25:45)
Continuity mistake: Both when Gale speaks into the microphone saying "Tell us everything that's happened", and when she wags her finger at her motioning her not to punch her, her hand is at heights inconsistent between shots. (00:25:15)
Continuity mistake: Sidney and Dewey begin their chat. In the wide shot, you can see that a girl is passing by the gazebo, behind it. She does it again in the next closer angle on the two talking, starting from way back. (00:22:50)
Continuity mistake: When Gale tells Debbie off giving her a nasty 'quote', the sun shines on Laurie Metcalf's sleeve in the angle where she says "Great!" and does not in the ones before and after. She is left standing in dismay, and you can see her in background with the sun casting another entirely different shadow even if she didn't move. (00:20:05)
Continuity mistake: Debbie Salt introduces herself to Gale Weathers and asks her a question that Gale does not like, so much that she puts her hand on Joel's camera and points it away, downwards. At the cut though Joel's camera is back up. (00:20:00)
Continuity mistake: When Mickey mentions Godfather Part II, there are reaction shots on the other students who have to agree on that statement, but their positions are inconsistent between shots (for instance the girl with the blue shirt has both hands joined at first, then at distance, the girls on the background to her right are leaning towards each other at first, then not, etc). (00:17:00)
Continuity mistake: In her opening shot, CICI says that you can't blame violence on entertainment. Behind her, out of focus, there's a student with a beige shirt. You can see his left hand, but in the next shot he has his right arm crossed on top of it. The rest of the scene goes on with that extra's motions not matching at the cuts (he's touching his chin next time, then he isn't). (00:15:20)
Continuity mistake: When Sidney grabs the caller ID device, the position of her fingers on it change between shots. (00:12:30)
Continuity mistake: When Maureen's boyfriend reveals not to be Maureen's boyfriend at all, the height he holds his knife at changes between shots. (00:10:25)
Continuity mistake: When Maureen goes back to her seat and starts putting on her jacket, the dude at her side begins waving his arm super-enthusiastically making happy coos. She finishes putting her jacket on and the guy, who is still making those sounds in dub, is sitting composed. (00:07:05)
Continuity mistake: When Maureen and Phil arrive in the theater, immediately at the beginning before the camera even gets fully in focus you can see by the door a blonde girl putting on the Ghostface hood, with her partner helping her. The camera cuts away for a second, and in the next wide shot you see her repeating the gesture. (00:01:40)
Deliberate mistake: It's a humorous twist that Randy's killing is covered up by some random guys passing by with a ghetto blaster, but there was dead silence when Randy was talking earlier; not being in frame does not block soundwaves. (01:05:15)
Other mistake: Ghostface tries to kill Sidney by the front door of the sorority house, and the pendulum clock shows it's 12:10, which fits also the timeline with CiCi's murder. Running away from him though, Sid passes by a mantle in the party room that has a clock that strikes 10 to 7. (00:39:40)
Character mistake: The library of Windsor College is awful at cataloguing, since Sidney searches the "Social Sciences" section and her screen is full of books about Quantum Physics. (01:06:35)
Factual error: The part of the play Sidney stars in begins with "All, behold the dreaded fate of Troy, that once stood proud and light upon the hills of Sparta." Please, what? There is a correlation between Sparta and Troy (the bride of the king of Sparta ran off with the prince of Troy, that was the casus belli), but phrased this way it does not make sense. (00:57:00)
Other mistake: The movie is supposed to happen "a couple years" after the previous (words of the moviegoer behind Jada Pinkett) but the current date shown at the theater says 1997, and Scream was set in September 1996 (calendar at Stu's house distinctly visible when he brings Sid's dad out of the closet).
Answer: His main motive was fame, or infamy for that matter.