The workshop set seen in the film's climax also featured in Dario Argento's Inferno (1980), Luigi Cozzi's Contamination (1980) & Antonio Margheriti's Cannibal Apocalypse (1980). It was an interior set at Des Paolis Studios in Rome.
One of the zombies is clearly wearing a Boris Karloff Frankenstein mask with extra gore and a wig added to obscure its origins.
Filmed on location at a real castle.
Shot in four weeks.
Filmed at Villa Parisi. Close to Rome, Italy.