Revealing mistake: Jennifer swipes her card the wrong way at the studio and the door opens anyway. (00:57:15)
Revealing mistake: When Sarah (the one who's supposed to play 'Candy') is stabbed, her blood is dried when she slumps over the door. (00:27:10)
Revealing mistake: Stunt double is visible when Dewey falls down the steps at Milton's house. (01:27:00)
Revealing mistake: When the house blows up and Dewey, Gale and Jennifer jump off the balcony, we find that Gale is near the car, the killer jumps up behind her. Dewy takes a shot at him with a gun and it is obvious that the killer awkwardly slams himself against the car window, rather than being caused by the impact of the bullet.
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)