Revealing mistake: When Frank yells stop to Marion, you can see the marks on the road from a previous take. (01:05:20)
Revealing mistake: When Lorraine dies after being shot (among other things), you can see her breathing clear as day.
Revealing mistake: When the car skids to a halt when they are chasing after Brad, for the speed they are traveling, the braking distance is way too short to be realistic: 85mph to 0 in the space of three car lengths on a wet road. (00:16:35)