The Congress, Ari Folman's first film since his international breakthrough with the animated pseudo-documentary Waltz with Bashir, is surely a broken-down disaster of a movie, barely able to function as an entire self-contained object. But I am absolutely confident that I wouldn't be half as thrilled by it if that wasn't the case: like far, far too few movies out there, it offers the sight of a filmmaker clearly working without a net, pursuing enormously challenging ideas, and experimenting with strictly visual means of expressing them. If the resulting film is a sometimes inscrutable mass of surreal, psychedelic moments strung along a narrative that feels like it's made out of at least three completely irreconcilable parts, oh well. I'd rather watch something with The Congress's absolute fearlessness to make every possible mistake than a polished, functionally flawless, but completely unimaginative stock character drama or popcorn action movie every day of the week.

The movie features Robin Wright as a heavily modulated version of herself, in a role that Folman initially intended for Cate Blanchett (the shift was critical, and correct: it requires a certain kind of "you used to be in pictures; you used to be big" backstory that Blanchett c. 2013 can't claim, but Wright absolutely can). And if Folman's bravery in his storytelling and artwork is admirable, Wright's bravery is incomparably more personal and affecting. She's anchoring a movie about the difficulties that come to women as they age, depicting herself as a prickly, unemployable, "difficult" actor, and allowing Folman and his international team of animators to render her as an exaggerated caricature for a great chunk of the second half. The movie's very first shot says it all: the camera is right in Wright's face, catching her distant, sad look, making her look heartbreakingly beautiful but also every day of 45 years old. I can't recall a single image in a long time that so perfectly sums up the sheer fact of what aging does: leaving a woman who is still remarkably pleasant to look at, but who's not the dewy ingenue that she sees a little while later staring out from a poster for The Princess Bride.

This matters - both the fact that Wright has visibly aged, and the fact that she still looks better than most of us on the most beautiful day of our life - because The Congress is in large part an exploration of the ways that people try to avoid acknowledging the aging process, in some increasingly metaphorical and deranged ways. Opening in live action in something very close to the present, Robin and her agent Al (Harvey Keitel) field inquiries from the slick Jeff Green (Danny Huston), a high-level executive at Miramount Studio, to buy her digital likeness rights. That is, to scan every inch her her body and her every facial expression to make a computer-based Robin puppet to be placed into any movie they like. And Robin can no longer perform anywhere: not in movies, not on TV, not onstage, not on open mike night. The very idea appalls and infuriates Robin, but the increasing sickness of her son Aaron (Kodi Smit-McPhee), suffering from a rare disorder that is slowly destroying his eyesight and corrupting his ability to process auditory information, and the unexpected, uncharacteristic support of her daughter Sarah (Sami Gayle) nudges her into reconsidering.

20 years later, at the very end of the exclusivity contract she signed, Robin drives into the desert to attend Miramount's grand Futurism Congress. Here, she is forced to snort a drug that alters her perception to believe that herself and everything around her are animated; and it's in this bizarre alternate world that she learns of Miramount's new plans for an interactive new storytelling medium, in which persons can ingest chemicals that will allow them to experience other person's lives from the inside out, not just mimicking their outward appearance, as many of the Congress attendees enjoy doing. And even that's not the last enormous narrative leap that The Congress makes, but the last one that I can describe without collapsing into spoilers, and also spouting out random nouns that might suggest the shape of the increasingly convoluted, metaphorical narrative, but certainly couldn't spell it out in a useful way.

Folman based his script on Stanislaw Lem's The Futurological Congress from 1971, a book I have never read; though some elements that feel like vintage anti-Soviet symbolism creep through, in bits like the description of Miramount's new chemical experiments as allowing people to experience the free will they are actively denied, or creation of persons forced to do any job the studio wants, with absolutely no choice in the matter. Mostly, though, it's a free-for-all of themes and interests and styles. How people interact with an increasingly synthetic world of screens and people whose chosen identity elides their real one? The Congress looks at that from both pro- and anti- stances. The degree to which new film technologies count as "acting", and what happens as computer filmmaking replaces real flesh and blood people, I mean, that's obvious. The value of fantastic lies versus miserable, filthy realities - not developed very well, but it's vividly presented in film's final sequence.

The effect is less of being presented with an argument and its supporting evidence, than being blasted with ideas at a nonstop pace, and realising only after it's all done how very random and arbitrary some of the shifts between those ideas actually were. Still, ideas are better than the absence of ideas.

And what really matters about the film is the language and style through which those ideas are expressed: after Waltz with Bashir, Folman needs to prove nothing else about his control of animation style, but I was pleased by the frequently gorgeous images that he and cinematographer Michael Englert and production designer David Polonsky were able to concoct. The scene of Robin being scanned is one of the most beautiful sequences of science-fiction I've seen lately, with dramatic, flashy lighting and sets contrasting with Keitel's soft monologue in a simply terrific way.

Of course, the animation that takes up a good half of the two-hour movie is more of an obvious, overt standout. Taking his cues from the animation of the '30s, the Fleischer brothers especially, Folman and his teams create a bright world of shiny grotesques, morphing and slipping and looking inhuman and warped but also soft and round and appealing. And the wildly old-fashioned style makes the highly un-'30s intrusion of moral blackness and violence far more startling than they might otherwise be. There's plenty of overreach - some of the LSD fantasylands of the last portion of the film feel like lazy '70s album cover design - but the fludity and creativity of the animation is a top-notch example of the medium being used in an apparently standard way to achieve entirely deranged goals.

For all that, though, this is Wright's movie. She's only seen in her own flesh for a little while, but the impact she makes with that time is enormous: stiff and stern and defensive most of the time, but melting in calmness or self-doubt in moments that hit with explosive force. It's not just the bravest work of Wright's career, but surely among the best performances she has given, even when she's just providing the reflective, regretful voice to a weird caricature of herself as an old woman. There is steel-like human strength and frantic animal terror flowing into each other throughout her work in The Congress, and while it's certainly a great if wildly inconclusive work of style, Wright always pulls it back to being, ultimately, about what human beings feel, and that's what makes it, through all it's indescribable weirdness, a marvelous and compelling piece of cinema.