The five films of director Darren Aronofsky have covered more conceptual and visually idiomatic ground than the entire careers of filmmakers with five times the output: a surpassingly cheap and grimy thriller about a paranoid mathetmatician, a whirling two-hour music video about drug addiction, a CGI-addled fantasia on the meaning of time, mortality and identity, and social realist biography of an athlete's one last chance. What has combined them all is the grand them of Obsession: if you are an important character in an Aronofsky film, it is very likely that there is one thing you want above all others, and in pursuit of that thing will sacrifice every relationship and comfort you know.

And here we have Black Swan, which is both a new genre and mostly a new visual style - it's the story of a sexually-repressed ballerina going nuts under the pressure of having to dance Odette/Odile in Swan Lake, filmed in a handheld vérité style in a similar manner to Aronofsky's last feature, The Wrestler, but with a whole added dollop of the creepiest-crawliest body horror of 2010, and metaphorically laden psycho-terror that reminded me, if anything, of Roman Polanski's Repulsion - and is otherwise the most Aronfskian movie yet: Obsession is its heart and soul, its bread and butter. Specifically, the obsession with perfection, both aesthetic (the ballet) and moral (the heroine's mother-instilled abhorrence of sexual impurity).

The ballerina in question is Nina Sayers (Natalie Portman), the daughter of a former dancer named Erica (Barbara Hershey), who gave up her own career when she became pregnant, and has become quite the stage mother in the interim, closely monitoring every minute detail of Nina's life and driving the younger woman - not so young, in her middle or late twenties, and still living with her mother in a bedroom without a locking door and too many tacky ballet-themed stuffed toys to count - to neurosis; we get the understanding that there have been other dark moments in Nina's life wherein the pressure of being Erica's pride and joy led her to acts of self-mutilation. Having caught the eye of the lascivious impresario Thomas Leroy (Vincent Cassel), Nina is cast as the bipartite lead of Tchaikovsky's ballet, the white swan Odette, representing virginal purity, and the black swan Odile, representing carnality.

Lacking the requisite sexual history to convincing play Odile as smoldering and seductive as Thomas demands, Nina is driven to frustration and then worse, particularly in light of the new corps member Lily (Mila Kunis, who won an acting award at Venice), who is raw and physical in all the places that Nina is fragile and chaste, and whose stand-in work as Odile is precisely the sensual ravishment that Thomas is looking for. As Nina goes crazy under the demands of her director, her own sense of personal failure, her mother's smiling harpy wickedness, and her uncertain feelings towards the now-friendly, now-scheming Lily, Black Swan falls steadily apart, yoking itself more and more to the hallucinations and waking nightmares that begin to define her perception of the world.

It is, by all means, a grubby melodrama, with loving attention paid to such details as Nina's tentative masurbation sessions and her terrifying visions of a doppelganger who might be Lily lurking and waiting to kill her, and the inexplicable scars and physical deformities afflicting the body that she views with something akin to visceral loathing. But I, for one, generally prefer Aronofsky in his grubby phase; and now is as good a time to admit at any that even when I admire his work the most, I find his films generally unlikable. His aesthetic choices strike me as no choices at all, but a whirlwind of activity, tossing every idea that comes into his head in front of the camera, simply because it excites him. And while they all have energy to spare, Aronofsky's projects are thus as much annoying for their obvious squandered potential as they are exhilarating for what they do accomplish - which is always considerable.

This approach probably works better in a horror film than in the other genres the director has attacked, and while, make no mistake, Black Swan is never going to end up on the shelves next to Black Sunday, the moments of greatest impact in the movie are almost exclusively the most classically horrific. As Nina grows certain that she is herself tranforming into the black swan, the rippling of CGI gooseflesh across her body, and the spontaneous eruptions of blood on her hands and feet (one particularly bracing scene witnesses Nina tearing a long strip of skin off her finger - or so she thinks) have an intensely unsettling effect, more genuinely upsetting than anything an American horror movie has been able to come up with in several years. And, it must be said, Aronofsky is just as willing to indulge in cheap tricks (the number of false jump scares is unforgivable for a movie with this kind of art-house credibility), though the body horror much outweighs the slasher-movie theatrics, as does the good old fashioned "this isn't right tension", omnipresent in the film from its dramatic opening scene, a dream in which Nina as the white swan is menaced by the ballet's villain von Rothbart, skulking in the inky shadows surrounding the dancer.

And if Black Swan were content to remain a grubby horror film, I guess I wouldn't have a word to say against it; but its dives into psychological investigation are so damned important, and so mostly flat, that it tends to suck some of the energy away from the very real successes onscreen, just like something has in every other Aronofsky film. For starters, the use of symbolism is about as subtle as a grand piano to the head: the black/white imagery is of course inherent in Swan Lake itself, but there is a material difference between ballet, the most abstract of all narrative forms, and cinema, nominally the least abstract; at any rate, while the color-coding is at times clever and at time haunting, I don't know what value it serves the movie that every single time we see Mila Kunis until the very end, she's draped all in black. The central idea of the ballerina - every clichéd little girl's dream job, and an opportunity for the repressed Nina to exert control over her body - is underdeveloped except as a plot hook (it helps not at all that Portman and Kunis, though game, are not as good at ballet as the film suggests they are, or requires them to be), with the film not even exploring the characters' milieu as thoroughly as The Wrestler did.

Frankly, I don't know that the director, working from a rather programmatic script by Mark Heyman, Andres Heinz, and John McLaughlin, really cares that much about Nina, who is treated very much as an object and not as a personality in his framing (the famed Aronofsky "back of the head" shot is much in evidence), and who is relegated in the story to an entirely reactive character, which gives Portman almost nothing to work with, leaving the actress stranded in a whole lot of variations on the same basic "confused and scared" face. Until the last twenty minutes, anyway, the only time that the film opens up whatsoever and the dramatic force of the plot catches up the the rich visual style that is so much more apparently interesting to the filmmakers. And by all means, Black Swan looks amazing: Matthew Libatique's harsh Super 16 cinematography is one of the great achievements of the year, plunging blacks and blinding whites and not a whole lot else, with grains the size of half dollars adding a thick veneer of texture that makes the film seem at once more real and more abstract, like a tactile fairy tale (certainly, Black Swan is a fairy tale if it's anything).

It's a damn chilly film, though with little genuine insight into the human condition and no interest in providing such insight: only a problem because the film sets it up in such unmissable terms that it shall be very much a character study. I suppose there's something compelling in its depiction of a mind descending into utter madness, viscerally if for no other reason; but it's just not that strong as a vision of the crazy artist, or the sexually repressed woman. Even as a story of the ballerina broken by her desire to achieve perfection, it says nothing that wasn't said with infinitely more success in the 62-year-old The Red Shoes. Yet there's no denying that the thing gets deep under your skin. It gets there in just about the least-reputable way it could, but it certainly gets there.