Walter Ruttmann's masterpiece, Berlin: Der Sinfonie der Grossstadt (1927) can be seen in full on this site HERE. Above, though is his op 3 from 1924, described as a Lichtspiel, a "play of light", where the action is generated by the very process of filming itself. Visually, they're not a patch on other experimmental films of the period, such as those by Marcel Duchamp, Fernand Léger, Hans Richter, Man Ray, Viking Egglund and so on. Indeed, Ruttman's op 4 (1925), a symphony of black and white stripes looks static compared with Duchamp's Anémic Cinéma (1926) where the lines form psychedelic whirling spirals, inspiring many Op Art copies in the 1960's. Conceptually, though, Ruttman's films are adventurous because they are experimenting with the very idea of using a visual medium in a non-visual way, deliberately challenging the senses.
The film above is interesting too because it was meant to be heard with Hanns Eisler's Passacaglia. No sound recording then, but I think this was meant to be screened together with live performance. Cinema musicians in the 1920's were far more sophisticated than many assume today. Thousands of formally trained musicians worked in cinemas, hotel lobbies, restaurants, ocean liners etc. Some were of course playing popular dance tunes, but in theory there's no reason why they couldn't play art music. This film bridges the social divide. It also combines film with music. (See Leger's film, also 1924, with Antheil's music in Ballet Méchanique HERE on this site).
Thus it connects to Berlin der Sinfonie der Grossstadt, made only 3 years later, where visual images function like musical elements, . Like a symphony, the film is structured around movements each of which develops a theme. Within each theme, images move and intertwine, creating a collage almost more musical than purely visual. Again, conceptually, it's an altogether different way of thinking about film. It's an apotheosis of film as art. It doesn't pull emotional heartstrings in the way that, say, The Thief of Bagdad or The Sheik whipped their audiences into a frenzy. No "movie stars", but real people going through their normal lives.
Perhaps I shouldn't read too much into this politically, but there may well be a connection between the way swashbuckling movies play on primitive emotions, and celebrity stars substitute fantasy for individual freedom. Perhaps Leni Riefenstahl's Triumph of the Will can be seen as a type of Hollywood extravaganza. albeit with particularly evil subjects. There is a line of descent from D W Griffith's The Birth of a Nation, and thus a loose connection even to Cecil B DeMille's more lurid "religious" biopics. Poor Ruttmann, whose experiments with modernsm were decidedly entartete, ended his life working at Ufa. At least, when Eisler went to Hollywood, his views on film were different. .