This film is part of the interesting John Ford at Columbia box set, in that it is a collection of films by John Ford that you would not think were John Ford films (another is Gideon's Day which follows a day in the life of a London policeman and is a curiosity worth seeing).
Edward G. Robinson plays the dual roles of a mild-mannered ordinary guy who works in an office and has fallen in love with the sparky modern gal played with great energy by Jean Arthur, but he is also the ruthless murdering gangster who is an unlikely double. Drama and comedy combine as the two men get mistaken for each other, in a movie that succeeds largely because Edward G. Robinson absolutely nails the distinctly different mannerisms of the two characters he is playing, to the extent that as an audience we need no dialogue to figure out who's who.
This is a wildly entertaining film, and audiences of the time must have been dazzled by the visual effects. To a modern audience, the back projection looks a bit obvious, but in one of the extras on the disc Leonard Maltin claims there is a scene where two Edward G. Robinsons are talking to each other within the frame: one is smoking and as he exhales, the smoke wanders in front of the other Edward G. Robinson. It's difficult to figure out how that was done with the technology of the 1930s.
If you enjoy Hollywood movies of this period, this one should suck you in within the first three minutes - quality popcorn fare from the golden age.