The way the ashes lie on the spoon between shots, near the end of the movie.
The words "My boy" appear written on different parts on the back of the old photograph depending on if it's a wide shot or a close-up.
The sound of the horror film that Katrina is watching (Ghost Ship (2002)) does not match the scene that is shown.
The graveyard scene at the beginning of the film was supposed to be set somewhere in southern California, as this was before they began their road trip to New Mexico. However, in the background you can catch a few glimpses of the Albuquerque skyline.