Two scenes where deleted from the final cut of the film. One of them was after Chaco leaves the group for dead, an injured Clem crawls on his wounded leg and unties Stubby. This scene was deleted because it dragged the film on. Despite the fact the scene was deleted it was seen on one of the lobby cards issued for the film. The other scene omitted from the film was a full blown love scene between Stubby and Bunny, but it was deleted because it was considered excess. To this day the scenes are considered lost or have yet to be discovered.
Director Lucio Fulci clashed with screenwriter Ennio De Concini over the script. Disliking what Concini wrote, Fulci took it upon himself to rewrite the entire screenplay.
Tomas Milian was so in character during the scene where he raped Lynne Frederick that he actually made Fabio Testi quite enraged. The anger on Testi's face in the film is real.