Someone's hood is shown in the beginning of the scene, then is shown off and then back on again in an incorrect order.
In one scene you can see the cinematographer's yellow sweater in the reflection of a window.
In one scene, you can see chopped onions. The onions were used to make the actors' eyes red, and were in the shot by accident.
In mirror, screen or window reflections, you can often see the camera and the person who is filming.