Revealing mistake: When Millie jumps on her shop teacher's back, the teacher switches from the actor to a stunt double as they begin to tumble about. Noticeably, his hair suddenly gets much darker and has less gray in it. You can also get brief glimpses of his face, and it's obviously not the actor.
Continuity mistake: During the final fight at the very end of the film, pay attention to Millie's bloody nose. At first, there's an equal amount on either side. But a few seconds later, the suddenly less blood on the left side of her face and more blood on the right side.
Continuity mistake: When Josh's mom is about to cut the Butcher/Millie out of the chair, pay attention to her right hand, which is holding the knife. Right before the Butcher/Millie springs up, as she's talking to her son, her arm goes from down by her side with the knife pointed down, to up by her chest instantly between cuts.
