The closing credits run for 11 minutes. This is because without the extra time, the movie would have been considered too short to release theatrically.
The sound of Matilda Dixon's wailing throughout the film is really the sound of an elderly woman's groaning in bed. The sound was both sped up in the parts where Matilda screams, and slowed down in the places where she gurgles and breathes heavily.
The lead character, portrayed by Chaney Kley, is afraid to go to sleep because of his recurring nightmares. Kley died in his sleep from an apparent breathing problem, which his father believed to be sleep apnea (the autopsy revealed it to be a drug overdose, however).
The theatrical poster has an MPAA R rating posted at the bottom, however the film is rated PG-13 by the MPAA.
(at around 45 mins) The "Sensory Deprevation Tank" is actually an MRI machine.