At the beginning of the movie when the pickup truck swerves around the girl, the tire squealing sounds like the road surface is asphalt, when it clearly is dirt and gravel.
When Bitsey Bloom was watching the tape in the motel room before she asks Zack to go re-create the crime scene. A quick short close up of Zack sleeping showed him wearing a watch. Before and after this close up he was not wearing one.
At about 2:13 into the trailer, somebody fires a black gun. I didn't notice that part during the movie. Was it maybe a symbol to mark the time of execution?