[181] Kracauer described the film as an example of Germany's obedience to authority and failure or unwillingness to rebel against deranged authority,[182] and reflects a "general retreat" into a shell that occurred in post-war Germany.

Abel Gance called it "superb" and wrote, "What a lesson to all directors! And though nearly all German Expressionist films have elements of film noir, M basically operates as an early and influential example of the genre and style.
[4][5][9] The experience left him distrustful of authority,[4][6] and the psychiatrist served as a model for the Caligari character.

[91][92] The original title cards were tinted in green, steely-blue and brown. This film, based on Jewish folklore, tells of the construction of a large mythical being made of clay (played by co-director Paul Wegener). [202] This, Barlow writes, "reveals a contrast between external calm and internal chaos". [24][51][59] The sets are dominated by sharp-pointed forms and oblique and curving lines, with narrow and spiraling streets,[92] and structures and landscapes that lean and twist in unusual angles, giving the impression they could collapse or explode at any given moment.

The creature is created to help bring justice for Jewish individuals, but things take a murderous turn when he becomes controlled by the spirit Astaroth. It’s the story of a hypnotist (the title character, played by Werner Krauss) and Cesare (Conrad Veidt), a sleepwalker he instructs to murder citizens of a small city. The film is not about him, however, so much as it is about the city’s response to his spree, from the police to the underground crime syndicate.

[85] Mike Budd notes that, during the scene in which asylum doctors restrain Francis, his movements closely mimic those of Caligari from a similar scene during the main story.
[71] Likewise, the scene with the criminal in a prison cell features a set with long vertical painted shadows resembling arrowheads, pointing down at the squatting prisoner in an oppressive effect that symbolizes his broken-down state. [106] Even within the main narrative alone, Caligari lives a double life: holding a respectable position as the asylum director, but becoming a hypnotist and murderer at night. This film also experiments with a new genre for the movement, as it is an influential example of a science fiction film. Francis and his friend Alan (Hans Heinz v. Twardowski), who are good-naturedly competing for Jane's affections, plan to visit the town fair. [75] Janowitz claimed he wrote the part of Caligari specifically for Werner Krauss, whom Deutsch had brought to his attention during rehearsals for a Max Reinhardt play; Janowitz said only Krauss or Paul Wegener could have played the part. [154] Caligari helped draw worldwide attention to the artistic merit of German cinema,[52][127][128] while also bringing legitimacy to the cinema among literary intellectuals within Germany itself.

Stephen Brockmann, Anton Kaes and film theorist Kristin Thompson say it was popular with both the general public and well-respected by critics. [143] Robinson argues this led to the rise of a large number of film designers – such as Hans Dreier, Rochus Gliese, Albin Grau, Otto Hunte, Alfred Junge, Erich Kettelhut and Paul Leni – and that effect was felt abroad as many of these talents later emigrated from Germany with the rise of the National Socialist German Workers Party.

Even the noirish lighting is more refined here, taking on a chiaroscuro form so that we can see the contrasts between light and dark very clearly. Four years after Fritz Lang released a quintessential German Expressionist film with Metropolis, he made a film that remains part of the movement while also signaling a move away from it. Kaes noted other parallels between the film and war experiences, noting that Cesare attacked Alan at dawn, a common time for attacks during the war.

[81] However, David Robinson notes even the performances of the more naturalistic supporting roles in Caligari have Expressionist elements, like Hans-Heinz von Twardowski's "strange, tormented face" as Alan. [210] The film had few similarities to the original Caligari except for its title and a plot twist at the end,[207][211] in which it is revealed the story was simply the delusion of the protagonist, who believed she was being held captive by a character named Caligari. [41] Janowitz claims the writers sought legal action to stop the change but failed.