The DVD commentary by actors Catriona MacColl and David Warbeck was recorded two weeks before Warbeck's death from cancer. In the commentary he talks about his illness.
Bob Murawski of Grindhouse Releasing - who restored the film in 1998 - is a film editor and used a shot from this film in the spider-bite dream sequence in Spider-Man (2002).
'The Book Of Eibon', featured prominently throughout the film, is the creation of American pulp fiction author, poet and fine artist Clark Ashton Smith and is a recurring text associated with the "Cthulhu Mythos" cycle of literature initiated by the works of H.P. Lovecraft. The book, which deals with various arcane subjects including the resurrection of the dead, demonic magic, parallel dimensions and other black magic subjects is alleged to have been imparted to the infamous necromancer Eibon by the ancient devil-god Tsathoggua in a remote prehistoric epoch. The book was introduced in Smith's 1933 short story "Ubba-Sathla."
Swedish rock band Europe based the song 'Seven Doors Hotel' from their first album on this film. The lyrics are a basic retelling of the plot of the film. The song became a big hit in Japan, and is still a popular track at their live shows.
This film was never seen in America in its uncut form until 1998, when Grindhouse Releasing tracked down the original master and restored the film, playing it at midnight shows at selected cities. Quentin Tarantino's Rolling Thunder Pictures released the restored DVD, as it was his favorite supernatural horror film when initially released as "7 Doors of Death" in 1983.
Lucio Fulci: (at around 49 mins) the librarian who goes out to lunch, right before the Architect is attacked by the spiders.
Lucio Fulci: (at around 33 mins) when David Warbeck answers the phone at the Jazz saloon, the director is reflected in the mirror behind him.