This demented fusion of Dr. Jekyll and Mr. Hyde with the legend of Jack the Ripper marks one of the final roles for
Anthony Perkins, and certainly one of the weirdest performances of his career. Perkins plays Dr. Jekyll as more of a dedicated 19th-century man of medicine than an obsessed eccentric -- whose research into a safe form of anaesthetic leads to the accidental discovery of cocaine! Jekyll's inadvertent freebasing of the vapors from a cocaine/ether mixture triggers his transformation into Hyde - a murderer of prostitutes who dubs himself "Jack," thus allowing the convenient transition into the "Jack the Ripper" phase of the plot. This Hungarian production has fairly high production values, but Perkins' over-the-top antics and some glaring anachronisms (Jack's streetwalker victims sport accessories that look like Madonna's hand-me-downs) make it impossible to take seriously as a horror film. ~ Cavett Binion, All Movie Guide