A very effective film that works due to its streamlined plot, some good direction, having Karloff and Lugosi involved and an outstanding performance from Stanley Ridges. The latter may be third billed but he steals the film from everyone. Bela Lugosi is no gangster but he wasn't really in a position to turn down any roles. Boris Karloff once again plays the mad scientist, albeit without his usual sympathy. In "Black Friday," he is a more devious and conniving character. Anna Nagel - the studio's original scream Queen before Evelyn Ankers replaced her - plays a gangster's moll. It is a pity that Karloff and Lugosi don't share any scenes as it would have added something. This is still a well above average film. Enjoy!