Producer Erwin C. Dietrich put his faith in director Jesús Franco and left him to make the film in peace, he did not see any footage until the film was finished. When Franco screened the completed film to him, he was horrified by the quality. The shots were too blurry and no movie lighting was used, it was rough and raw. Franco defended the film and explained it was the style he was going for. Still dissatisfied, Dietrich told Franco it was a terrible film and wasn't sure if he would be able to sell it to theaters. However, much to Dietrich's surprise, he managed to sell it to numerous European cinemas and the film was a decent success at the box office and received several good reviews at the time. Many years later, in an interview, Dietrich thought more highly of the film and said it was the first film to use the Dogme 95 style before Lars von Trier. Franco went on to make 16 more films for Dietrich over a three year period, and he told Dietrich they were the best years of his life.
Lina Romay was so comfortable being totally nude during her hours of filming, that she wouldn't bother putting on a robe between shots. She'd relax on set naked and even chat and eat with the crew.
To save money on shooting and editing the dream sequence in slow-motion, Jesús Franco just filmed himself and actress Lina Romay at regular speed while pretending to move in slow-motion.
When originally submitted for release in 1976, the British Board of Film Classification rejected it. It was only passed the following year after extensive cuts.