As usual in 'Jesus Franco' movies, the credits of the film contain different (and often incongruous with each other) info in every country's version. While the English version lists Peter Welbeck (nom-de-plum for
Harry Alan Towers) as the author of the screenplay, the Spanish version (with a credits sequence that replaces the exterior shots of the castle from the original with a cheesy drawing of a red dragon) lists
Manfred Barthel as the author of the story and screenplay, and
Jaime Jesús Balcázar as the author of the dialogue. This version also credits some actors (such as
Gustavo Re and
Osvaldo Genazzani) and crew members not credited in the English version, and the cast order is different as well.