Revealing mistake: In the opening scene where the alien car is pulled to the side of the road by the cop you can see two identical sets of tire tracks in the dust in the same place - a sign that this scene was filmed more than once in the same location and the filmmakers didn't wipe away the tracks. As the car pulls out you can see another set of identical tire tracks further up the road as well.
Visible crew/equipment: There is a scene in this movie where Emilio Estevez and his partner are sitting in a car outside a shop. The camera tracks in on them. The problem is the crew havent bothered to hide the camera track running from the bottom of the frame up under the car. There is a badly placed black mat that covers a bit of it but this just draws your attention to it.