Powell was well-known for his 1940s Technicolor fantasies, but when this film was released, it was so poorly-received that it effectively ended his career as a director, which is a shame. The film is a masterful portrait of Marc (Boehm), a killer who films his victims as he kills them and then watches their filmed expressions of horror. The story is a nightmarish tale of voyeurism and the heavy psychological toll it takes upon the voyeur, and though Hitchcock also made films about voyeurism, he tended to cloak them in the trappings of commercial suspense films, where Powell placed the theme front and center in the work. The film also works as an effective thriller, as police investigate the murders and Marc begins to fear that the law is closing in on him. However, the most chilling moments in the film deal with his compulsion to kill and to watch, which in his mind have become intertwined.