At two different times in the movie, when a call is ended on what is clearly an iPhone, the "charging" sound can be heard. This sound would only be heard when the phone is plugged in to charge, and would not make that sound when a call is ended.
When Jordan stumbles upon the trapdoor access to the underground bunker, it is covered with leaves and debris. But Michael is already inside, so the debris would have have fallen away when he opened the trap door.
Casey's arm (that was waving through the brake light hole) is already inside when the car exits the highway but in the immediately following scene, she is purposely shown pulling her arm back inside to allow her to look outside.
When police remove Alan Donato's body from the trunk of the Lincoln, the front of his white shirt is clean, despite the fact that Michael Foster had stabbed him in the torso multiple times with a screwdriver.