Continuity mistake: As the girls run from the killer, the one girl is shirtless as she starts to run, holding her shirt in front of herself to cover her chest. The camera changes to a rear view and now she is running with the shirt in her hand swinging wildly. The camera changes again and suddenly she is running and putting her shirt on, already pulled over her head, a major change from the last shot. Finally, the camera angle changes again and she has her shirt on completely. All of her shirt/hand positions change instantly between shots.
Continuity mistake: After Jenny is done speaking with Lars, she picks up a large platter of food and holds it like a waiter/waitress over her right shoulder. (this is a front view) The camera changes to a rear shot and suddenly she is holding the platter over her left shoulder. The scene switches back and she is once again holding it above her right shoulder. This changes back and forth instantly between shots.
Other mistake: When Pete is introducing his staff and they are all dancing on stage, there is a beautiful brunette who walks up and dances almost the entire time between Juan and Sam. She is supposed to be part of his staff. Yet out of the blue when the camera pans right before Sam interrupts Pete she disappears. Literally from the entire movie to never be seen or spoken of again. There is not even a name on Sam's activity board for whoever this mystery woman is.