First of all, I must admit that although I hadn't seen this film before, I have heard and read a lot about it. However, I was still amazed by the scale and drama of the actual film; apart from the acting and the fact that it's a silent film, it struck me as every bit as good as some modern films. Anyway, on with the review ^^;
This film is monumental in every sense of the word; from the iconic imagery to the (now cliched) story of love, revolution and disaster. However, none of this would be possible without the sets amongst which the action takes place. Produced in model form, the enormous city of skyscrapers so big that they dwarf their human occupants is a triumph of art deco design. The "tower of babel", from which Joh Fredersen looks over the city he created (and controls the running of), wouldn't look out of place alongside the empire state building, which it pre-dates by 3 years. At the same time, the sheer scale of the architecture is at times reminiscent of the work of Adolf Speer (which it again pre-dates). As Paul Brenner says in his review for Filmcritic.com, "(the)...massive production design that overpowers the actors on such a scale that they are transformed into moving masses of architecture themselves"
Whilst the "world above" is a triumph of art deco design, the "world below" where the oppressed working class toil to keep the "world above" running is another piece of classic set design, with mammoth machinery dwarfing its human slaves who tirelessly work to keep them in operation. This world is a much darker one, which serves to emphasise the disconnect between the two worlds, and is mirrored in the dark clothes of the grimy workers.
The film also makes good use of "dream sequences" to convey the hallucinations that the protagonist Freder Fredersen suffers, firstly upon witnessing an industrial accident, in which the machine is transformed into a monstrous temple, and the workers into sacrifices to it (which is of course closer to reality than most metaphors), and secondly when he is lying in shocked delirium, when the statues of the 7 deadly sins in the cathedral come to life. Both of these scenes use heavy symbolism to convey the subtext of the film in what appears to modern eyes to be a somewhat archaic fashion, but none the less they serve to illustrate Freder's motivations in a way that it is hard to better. As A. O. Scott says in his New York Times review, "Christianity, German romanticism, modernism and Marxism stampede through the movie like the crowds of angry workers and bourgeois revelers in the apocalyptic climax, but the confusion that results ultimately resolves into hallucinatory, visionary clarity"
Finally, this film is responsible for creating many of the images that we now consider to be the cliches of science fiction; from the mad scientist Rotwang, with his "just been electrocuted" hair and staring eyes, to the uncaring buisnessman, owner of all he surveys, Joh Fredersen; from the impersonal scale of the architecture to the robotic "mechanical (wo)man" built by Rotwang as a replacement for his dead love. In some ways, it is the film that almost all subsequent science fiction movies have been in the shadow of; as Roger Ebert says in his review "The ideas of ``Metropolis'' have been so often absorbed into popular culture that its horrific future city is almost a given"