Continuity mistake: In the scene where Rennie drives to the "Towers Motel" in the exterior shot the car is casting a shadow to it's left. In the next shot (interior view), the trees standing outside cast a shadow to their right.
Revealing mistake: After the El Dorado hits Boone's car and is just about to drag it, there is a quick glimpse of its front license plate. The letters are reversed, indicating that it is a flipped shot. (00:28:20)