The opening sequence is an introduction added by Sir John Boorman, at the request of Twentieth Century Fox executives, to help the audience understand this movie.
According to writer, producer, and director John Boorman, Sean Connery had a very hard time finding work after "Agente 007 - Una cascata di diamanti (1971)." Boorman was allegedly able to hire Connery for $200,000.
A real baboon on the set attacked a double, dressed in an ape suit who was portraying a baboon.
To help keep costs down, Sean Connery used his own car and drove himself during the production. Sir John Boorman then gave him half the money that had been budgeted to hire him a car and driver. The idea was Connery's, according to Boorman.
Cinematographer Geoffrey Unsworth filmed scenes with the lens wide open, fog filters on the camera, and smoke machines on-set to achieve a diffused, impressionistic look. It worked on first-generation prints, but when the film was duplicated for release, the image quality was so bad it was almost unusable. The studio forbade any cinematographers from using that process on future movies.
John Boorman: The slave forced into farming, whom Zed shoots. Boorman was shot with a blank, but wadding became embedded in his forehead, and took several days to come out.