The eerie noises in the movie are a mix of the sound mixer's voice with animal sounds. There was no money to pay for actors so the Mixer played all the spiritual elements of the film himself.
The 'demon cage' shown in the film belongs to the director.
The office used as the film's set was also the production office for the 15 crew members, with several people working literally from set.
The original script called for a final showdown in the building's lobby but budget constraints made the filmmakers adapt it to a different ending, which led to the creation of the Hollow Realm in the final film.
Janitor Jack's blood curdling shriek was performed by the director, who describes this yelling as "my highest artistic achievement yet".
