When Nell is cleaning hotel rooms, a picture of an owl with long legs can be seen on the wall. The picture is that of a demon called Stolas, as depicted in a 19th century French demonology text called "Dictionnaire Infernal".
As part of the promotion for the upcoming release of the film, a salon scare prank was set up in which an actress would hide behind salon mirrors and scare the customers (the actual prank is included on the DVD/Blu-ray release of the film).
The trivia item below may give away important plot points.
Was originally rated R by the MPAA for a scene where Chris slits his throat graphically until the scene was edited for a PG-13 rating (the unedited version of the scene along with some other deleted scenes were restored for the unrated DVD and Blu-ray release).