Continuity mistake: In the opening scene, Drew Barrymore put the Jiffy Pop on and it sizzled right away. In reality, it takes about ten minutes to heat up. And also she should have shaken it when it started sizzling. (00:01:25)
Continuity mistake: At the end when Sidney is in Dewey's police car and the killer is there, she opens the door and falls out but the door is still locked. In some cars you can open the door when it is locked but the lock always pops up after you open the door, and this one didn't.
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 though when he speaks to Tatum. (01:03:40)
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: When Casey starts making popcorn she places a metal condiment on a hand towel next to the cooker however when she returns, after talking to the killer on phone some more, the condiment is gone. (00:01:31 - 00:03:27)
Continuity mistake: At the beginning of the movie as Ghostface chases Drew Barrymore the killer is wearing a different style of mask and even has a shiny silver material rather than black. As the killer then sits on top of her then choking her, it is the more recognisable mask.
Answer: They didn't have anything against Tatum specifically, her death was just necessary for their scary movie plan against Sidney. They also said that anyone who isn't a virgin dies in a scary movie, and we know Tatum wasn't a virgin.