Though I probably haven’t seen enough thrillers to know, their general pattern seems to be lightheartedness through the beginning, and then a quick increase into whatever makes us anxious, a curveball at the end, finis. Except that this seems to be Hitchcock’s strategy, I’d say that Lang was working early in a genre–and so? I think the plot is marvelous–the police can’t find the murderer, so the criminals set out to do so. But what really illustrates that the film is more interested in character development, or, rather, social criticism as a result of that development, is that the film’s whole plot can be traced to a few moments in the middle of the film, when the criminals make their decision, and off they go, and their plan works without a hitch. So the criminal is captured, and the film hasn’t ended yet, and has a ways to go–and ultimately we’re stuck without a resolution to keep our minds off our own terrible indecision over the murderer’s guilt.
As soon as they mentioned the murderer’s being a sexual deviant, I thought “ah hah, I’ll bet this was used as antisemitic propaganda”–though the murderer does not look Jewish, and indeed, parts of the film were used later on as such propaganda, as the man playing the murderer is Jewish. Time to watch Mabuse again.