In my view, most reviews of this film have it all wrong. A crime thriller it most certainly is not. There is no thrill to be had in the discovery of the criminal since his identity is generously revealed in the very earliest frames. Not a trace of horror is generated by the murder itself since we are never allowed to see it. A balloon floating skyward is the only hint we are given of its enactment. Instead of murderer and victim, the protagonists that generate the compassion, the hatred and the anger of Lang's singular masterpiece are two competing systems of morality, one favouring the victim and the other the perpetrator. The final 'shoot-out' takes place in the grim warehouse to which M is brought by the criminals who have caught him in revenge for ruining their profession, and is 'tried' by a judicial process that in many ways comprises more of the elements of true justice than the conventional trial that follows when the hitherto inept Police interrupt the impending execution and drag him before the strong arm of the Law, where a parade of lawyers and psychiatrists mouth the usual meaningless platitudes that result in his acquittal by reason of insanity, to the dismay of the grieving parents of his 14 or so victims. The crooks seemingly got it right: they, after all, and not the Heidelberg-educated jurists and medics were his 'true peers', whose opinions are proudly supposed to count most in the traditional legal systems of Western Democracies.
Lang's main concern and his seminal triumph is to explore the impact of crime and a failure of retribution upon various layers of Society: Criminals, Police, Politicians, and the Public at large. His analysis is larded with wit, cynicism and satire, covering all aspects of the issue with all-embracing thoroughness, and he presents all sides so objectively that we never really know the nature of his own opinions and agenda. This is not surprising when we call up the fascinating extras included in this excellent Criterion package that reveal what a liar and dissembler this great artist was in his own life. But what an artist! The cunningly angled shots of sinister streets and buildings; the close-ups of individuals revealing almost every emotion that the human face is capable of displaying; the scenes of crowds moved by fear, anger, suspicion like a pack of animals; all of these skills are deployed to build up excitement and tension in the viewer as no film-maker achieved before or since, no matter how much blood and violence were lavished on the attempt. Much is made of Lang's role as a fore-runner of Hitchcock, but in my view this is not accurate in the sense that Lang was so far ahead that the latter never really caught up.In summary, we should all be grateful to Criterion for making available a remarkable piece of cinematic history so fresh and well-preserved that it comes across as history made contemporary.