When Brooke paints her nails in the bathroom, she takes polish off her right index and middle fingers. A shot is shown of her polishing the middle finger. The next time you see her middle finger there's no polish on it and she starts to polish it again.
At exactly 1:13:30 in the movie when the character of Tara is trying to escape from the killer inside the prop house she comes upon two doors with glass windows. At the bottom left of the screen a man from the crew can be seen sitting on the floor watching the actress play the scene.