I won't comment about the acting or plot -- there's plenty of that here already. What I'd rather do is call attention to the visuals -- the cinematography, lighting, costuming, and especially the set design.<br /><br />Normally, horror films take place in ancient settings -- crude medieval fortresses and rustic castles that are dark, cluttered and gloomy. But this one is set in a perversely utopian sci-fi fantasy -- the clean lined, impeccably detailed, generously glazed modernistic and (usually) radiantly lit white-and-silver upper floor interiors of the house.<br /><br />The lower floor is an expressionistic prison, also clean lined, but still dungeon-like with its windowless walls of exposed board-formed concrete. An elegant steel spiral staircase connects the two, and the angular expressionism reaches its culmination in the chamber used for the black mass.<br /><br />Karloff's costumes recall Oskar Schemmer's Bauhaus-produced work -- angular, broad-shouldered, narrow-waisted and elegant. Even the haircut of this man of the future in sharp and angular. His character is an engineer and architect and is given the name -- Poelzig -- of a famous expressionist German architect and film set designer of the time, who was a colleague of the director on an earlier film. The elegant futurism in carried down to the detail level, including a digital night-table clock and an abstract chess set. Much of the genius of this movie is that it breaks the horror-movie visual mold, and floods it with light, creating a fascinating tension between plot and setting.