Continuity mistake: For a moment, Cotton seems to have the upper hand against Ghostface as he pushes a bookcase on him. He eyes the golf club trying to take it back; in two consecutive shots though, you can see a Vance Bourjaily book (it should be "Now Playing at Canterbury" but you can only see the back cover) that faces opposite directions. (00:09:00)
Continuity mistake: The detective gives Gale the picture that she identifies; her thumb is in a different spot in each shot. (00:12:30)
Continuity mistake: Detective Kinkaid tells Gale "I'm here because Cotton Weary's been murdered." Behind him in the corridor, a girl that was at the conference, in overals and a loud pink top. Reaction shot on Gale, and in the background, in a different corridor, the familiar denim-and-pink-girl. (00:12:20)
Continuity mistake: Cotton agonizes on the floor with his right arm raised, but for the views with the camera pointed at the killer, his arm is lowered. (00:09:10)
Continuity mistake: In the action sequence where Cotton pushes Ghostface against the bookcase, the killer faces the wall, then at the cut he is facing Cotton before the case falls on him. (00:08:55)
Continuity mistake: Cotton arrives at his apartment; seen from behind, he leans into the door putting his right hand on the frame. Side view and he's leading with the left. Very similar mistake a handful of seconds later; look when he moves up the stairs. He gets one foot on the last step and it's the right foot, then it happens again, but it's the left foot that leads. (00:06:20)
Continuity mistake: Christine turns off the stereo. Look at her hair, and keep looking as she walks along the corridor. The hair keeps changing position over her shoulders between takes. (00:04:50)
Revealing mistake: Cotton is trying to reach his girlfriend using his phone. He shouts "Pick up the phone!" then curses because he has to quickly sverve. In the last shot of his maneuver at that crossing, two other cars have to zigzag to avoid a collision. Skidmarks which match their motions are already present on the asphalt, very likely from a previous take. (00:03:25)
Continuity mistake: Cotton is talking in traffic using his car phone. Notice the way he holds it in the very first shot; his pinky finger is behind the receiver, but it's on a different position after the cut. (00:00:35)
Other mistake: Cotton's opening line in the movie is that he won't go below 1 million bucks as he's risking his reputation for the cameo, furious that they can't write him a decent part for the Stab movie. So he's still negotiating, but the news story later in the movie says he filmed the cameo the day before.
Other mistake: June 28 was a Monday in 1999. Jenny McCarthy was killed the day before, so on a Sunday. The scene takes places the evening (there's sunlight when it begins) after the night scene with Sidney; it is however uncertain if it is actually supposed to be the same day, or the day before, a Saturday. Therefore, Cotton, murdered a day earlier, was killed on either a Friday or a Saturday, but when he was killed there was a promo on TV about "tomorrow's" episode of his talk show, which is on during weekdays and so wouldn't be on for the weekend.
Revealing mistake: The two faxes Jennifer reads are a single document that arrives with a timestamp of 21:05 at page 1, and of 21:07 for page 2. They arrive less than thirty seconds apart, and same for page 3, printed at 21:09. (00:44:20 - 00:44:50)
Other mistake: You can read the date of the event at Jennifer's house on the fax; it's June 28 1999. However, if you look at the director's office in the scene with Sarah, June was a very light month with according to the post-its mostly scouting for locations and such, and no shoots were scheduled in that month, as opposed to August that is full of those. All the previous scenes at the studio involved the actors on set for their scenes, and the news voiceover says that Cotton shot his cameo role the day he was killed.
Character mistake: Stone catches Gale snooping around and Dewey takes her aside to the kitchen to have a chat. She updates him about the latest news in the investigation, "Sarah's call didn't come from his cell phone." However Courteney Cox mangles the name and calls her "Sterra." Noticed by Wes Craven in the DVD commentary track; he even identifies the scene with "Oh, this is the scene when she calls Sarah 'Sterra' "and the editor references the similar "Roman=Ronan" mistake that happened earlier. (00:40:20)
Other mistake: Gale arrives at Jennifer's house for the party, rings the doorbell, but inexplicably, nobody answers. Noticed by Wes Craven in the DVD commentary; they said they "got away with it" by not adding the sound effect of the doorbell ringing in post so most people would Miss the gesture. (00:39:00)
Answer: No it was Roman. There is a technique you can do where if you apply pressure on the correct artery you can stop the pulse. EXTREMELY dangerous though.