Continuity mistake: At the beginning of the movie Margaret White gives birth to Carrie. She gets a pair of scissors out of a drawer and tries to stab Carrie in the face. When Carrie starts to cry Margaret picks her up and holds her near her face and the umbilical cord has disappeared. It was there before she picked Carrie up, and she never cut it.Aled Wesker
Revealing mistake: During the prom sequence, when the moon-shaped light fixture falls onto the stage supposedly "setting the stage on fire", you can see that it is a fuel line that is starting/controlling the fire.