The 2001 animated feature Metropolis, a science fiction parable about robots and class struggle in an incredible Art Deco super-city, has its work cut out for it twice over. First, it's living in the shadow of that other science fiction parable about robots and class struggle in an incredible Art Deco super-city titled Metropolis, the iconic 1927 silent epic directed by Fritz Lang that remains, close to a century later, one of the most visually influential movies in the history of the medium. Second, it has to live up to the entire career of illustrator, writer, and director Tezuka Osamu, likely the single most influential artist in the history of both manga and anime. Metropolis is based one of his earliest major works, a 1949 manga that Tezuka claimed was inspired by a single frame from the 1927 film, which he had not at that point seen; the 2001 film is a bit of a free adaptation that draws from both of those sources to create something not exactly like the comic and definitely not a remake of the older film, but something that serves as an homage to them both.

But what it really is, in its heart of hearts, is an attempt to bring Tezuka's characteristic style to life with bleeding-edge animation technique. As a story, Metropolis is rarely more than a bucket of reheated clichés, but visually, it's a splendid marriage of clear, strong digital painting and compositing with the bulbous cartoon aesthetic of Tezuka's medium-defining work in the 1950s. It's a marriage that works so well it's hard to put it into words: the digital animation gives the character designs volume and presence, while the genial roundness of the drawings lightens the weight of the fairly grave story, creating a mildly ironic juxtaposition that recalls the tension between charm and severity in several of Tezuka's own comics.

The script, by Otomo Katsuhiro (the creator of the incomparably important Akira), is a grab bag of ideas that do, if nothing else, feel honest to Tezuka's own concerns. In the city of Metropolis, the most technologically advanced place in the world, the much-admired public benefactor Duke Red (Ishida Taro) has just unveiled the Ziggurat, an extraordinary new skyscraper that will, he announces somewhat cryptically, usher in a new era of Metropolitan dominance. Given how open he is about that, it's no surprise that he turns out to be a megalomaniacal supervillain, and the Ziggurat is in fact a unimaginably powerful weapon, complete in all but one detail: it needs a controller to sit at the top of the tower to focus its energies. And Duke Red has just such a controller in mind: he's contracted the black market scientist Dr. Laughton (Takiguchi Junpei) to build a brand-new kind of artificial life, modeled after Duke Red's own dead daughter.

This gets complicated twice over. First, Duke Red's adopted son Rock (Okada Koki), acting in a jealous rage that he has rationalised as protecting his emotionally unavailable "father" from scandal, has learned of Laughton's project and taken steps to destroy it. Second, detective Shunsaku Ban (Tomita Kosei) and his nephew/assistant Kenichi (Kobayashi Kei) have arrived in Metropolis investigating Laughton. The upshot of these two wrinkles is that Laughton ends up dead and Kenichi ends up lost in the subterranean depths of Metropolis with the now-activated robot, named Tima (Imoto Yuka), who is slowly learning to build out her personality with the boy's help. He starts to fall in love with her, despite it being unclear if she can even mimic emotions, let alone feel them. Duke Red is, naturally, doing everything he can to find the two of them, as is Shunsaku. And this all plays out atop growing unrest as the robot underclass, gaining just enough self-awareness to begin resenting its status as slave labor, has begun to clash against the human of Metropolis, leading to the violent acts of the anti-robot Marduk Party, led by Rock.

That's a whole lot of stuff, arguably more than the film needs or knows what to do with ("Marduk" is a Babylonian reference to far, frankly), but it has the merit of keeping things moving. At 108 minutes, Metropolis leaves itself room for some quiet moments of stillness and solitude, generally focused on the growing self-awareness of Tima, but the main narrative strategy here is to keep throwing stuff at us, fast enough that it always feels driving and swept up by grand tides of history and fate, and enough that it's not always easy to realise, in the moment, that this is all pretty much science-fiction boilerplate.

Anyway, as I suggested back up top, the story itself simply isn't as interesting as what the film is up to visually. Some of what's going on is impressive simply in terms of combining three-dimensional CG environments with traditional cel animation; this is one of the big films in developing that hybrid form of Japanese animation, the film that ran where Ghost in the Shell merely walked. And to be sure, it walked fast. But nothing I can name from the whole corpus of Japanese animation prior to 2001 is doing as much as Metropolis, nor as well, to exploit the possibilities of computers to create and explore a vast, intricate, 3-D space. It's not flawless - the bigger an environment is, the more likely that at some point it's going to descend into bad texturing - but it's awfully impressive, and given how much of the film is about getting lost or overwhelmed in the inhuman bigness of Metropolis, this is a pretty necessary component of the whole.

And it's not just large-scale gestures, either: the film is suffused with little dimensional tricks, at the smallest level. Indeed, some of the moments that impressed me the most were among the least-stressed: a zoom as characters descend an escalator, carrying us along with them while emphasising our separation, or simply moments where multiple planes of character animation move relative to each other in different ways that I wasn't expecting. These are the moments that make this a full, elaborate world, one that breathes and moves in a living way.

But, to bring things back to where we started, what really matter most is the loving care with which director Rintaro and the animators at the great studio Madhouse have treated Tezuka's character designs. Tezuka famously had a "stock company" of characters who showed up across his career, generally playing similar types in different projects, and Metropolis is where a lot of them showed up for the first or at least second time. This film is thus somehow both a beginning and an end: it doesn't have just the designs, but the accumulated weight of these designs, and their importance not just in Tezuka's universe, but in defining the traditions of an entire medium. The film does extremely well by these designs, animating them at a framerate that Tezuka could never have afforded, giving the characters weight and volume and fluidity to go along with the bright, cheerful expressivity that their creator had already imbued them with. At times, Rintaro pushes things ever farther: the film's most striking shot is a close-up  of Tima, her head rendered in a lovely digital painting that blurs the distinction between flat and 3-D animation, while her hair whips around in the wind and the light. It's a stunning image that could never have worked out so well without digital painting, keeping the still drawing of her face and her fair from feeling too separate, and it's not just a lovely treatment of the simple, readable character, but a resonant emotional moment as well.

That mixture of beauty and bounciness ends up defining the movie's attitude: it is serious and a lark, visually fussy while also being clean and spare. It's lightness is maybe most clearly attested to in its energetic soundtrack, made up mostly of uptempo Dixieland jazz, a strange fit for anything other than "hey, remember the '20s?", but one that Metropolis uses to create a very strong, singular mood of pulp energy mixed with pulp fiction's ability to access bold, essential moral questions. The film is extremely lovely and a little bit lumpy, but its enthusiasm for what it's doing, and its guileless sincerity, make it a thoroughly engaging and satisfying tribute to the noble history of its genre and its form.