Demdike’s review published on Letterboxd:
The Black Room stars Boris Karloff as twin Czech brothers. They are plagued by a curse that foretells that," just as the family began with the elder twin killing the younger, so it shall end". The room of the title is the place where Gregor, the older brother, dumps the bodies of the local girls once he has had his way with them.
The Black Room is a very stylish period film, more Gothic melodrama than Gothic horror, never the less it is an excellent vehicle for Karloff to play against type in the role of the younger brother - Anton, who is a kind man,and allows Karloff's gentler qualities to come out more. He's on more familiar ground playing Gregor, the nobleman who strikes fear in the local population with his sheer presence. In either role though Karloff is outstanding. A special mention must also go to Marian Marsh and her superb porcelain features, who plays Gregor's object of lust, Thea, quite beautifully.
The films special effects are excellent considering it was made in 1935. The two Karloff's, in shot, whilst talking to one another in multiple scenes as though they were different actors. A great technical achievement by the production team. Roy William Neill, the director is best know for directing several of the Rathbone / Bruce, Sherlock Holmes films of the forties for Universal Studios.
Although the film was made by Columbia rather than Universal, the films sets are just as pleasing to the eye, lovely east European villages, stunning mansions and beautiful set design all add up to produce a finely crafted seventy minutes of entertainment.