Swiss Army Man is pretty great right up until it very suddenly isn't any good at all. I concede that is terrible film criticism, but I'm damned if there's another way to talk about the movie. You hear "farting corpse that you can ride like a Jet Ski" out of the Sundance Film Festival coverage, and your curiosity is piqued; you hear that it is by most accounts worth watching the farting corpse movie, and then there's no holding back. And the thing is, the farting corpse is barely even the hook; the farting corpse gets normalised within the first ten minutes of the movie and you start to forget about it. It's a weird-as-hell film, but the farting corpse is just about the least weird thing about it, and eventually it gets so weird that it breaks. So I return to my point: Swiss Army Man is pretty great when it's a buddy comedy about a man and his farting corpse - I am not sure that cinema has ever produced more consistently great fart jokes - and it's charming, funny, visually inventive, well-acted, and has a killer score. And then you can almost point to the exact scene when it all goes completely wrong, and it kind of ruins the whole thing. But as unsatisfying as I found it - as actively maddening, really - I am glad the film exists and glad I saw it, and damn me, but I think I would like to recommend it, even though it is indefensible as a good or even predominately functional motion picture.

Written and directed by "Daniels", the collective noun describing feature film newbies Dan Kwan and Daniel Scheinert, Swiss Army Man is a two-hander that starts on a deserted island in the Pacific Ocean, with heavily bearded, bedraggled Hank (Paul Dano) attempting to kill himself by hanging, while humming appropriately suicidal music to himself. His action is interrupted when a body washes up on the beach (Daniel Radcliffe plays it), expelling gases out of its decomposing anus at such a steady rate that, in short order, Hank is able to ride it out into the open sea. On the mainland, he drags it to a cave in a forest full of trash, and it's there that the miracle happens: the corpse starts to talk. It identifies itself as "Manny", but has no other memories; so Hank, in between bouts of trying to find his way out of the forest, explains all about humanity to his unconventional new friend. In the process, we learn enough about Hank's miserable love life and unresolved daddy issues that we can conclude pretty readily that restoring Manny's humanity is as much a project for the living man as for the dead one.

There are a lot of places this could go, and Swiss Army Man picks several different options, not always to its credit. In the beginning, though, it's at its best: a goofy, magical realist buddy comedy in which a sad-sack manchild uses trash-based arts & crafts to explain human emotions to a dead body that can only move its mouth. For the most part, the film refuses to make any commitments: it's always possible that Manny's unexpected vitality is strictly in Hank's mind, and the movie dances for a long time between the registers of cooing with sad sympathy for Hank's "I have lost and love and thus I am sad!" moping and gaily poking fun at same, playing like a parody of the sexless Nice Guys who used to be suffocatingly inescapable in American indie movies. There are some thoroughly inspired jokes, most of the best ones relying on the medium itself rather than the screenplay: the use of '90s movie as a shared touchstone leads to an extraordinarily good musical gag, and the film gets almost more mileage than it should be able to from snappy editing that turns physical spaces into collages and makes Hank's habit of building little dolls out of bits of garbage shift from something obnoxiously twee into a hilariously overwrought obsession (the best gag that the film never calls our attention to is that maybe, Hank and Manny could get home if Hank didn't spend all day building buses and cafΓ©s out of detritus). Hell, it's such a formally-oriented comedy that even the timing of the opening credits works as a joke - maybe even the best joke I've seen in a theater so far this year, gravely mocking the triumph of the fart-based ocean voyage.

All of which is magnificently charming even when it's not as-such funny, though there comes a point where Swiss Army Man becomes too enamored of its own giddiness. The magical world Hank builds for himself and Manny starts to pull the film down, infesting it with a pointed quirkiness of a sort that indie movies abandoned years ago, and not really doing anything with it: the protracted scenes of Hank in drag, teaching Manny about women, is particularly dire, a one-note joke that the film begins to take irritatingly seriously. It is, in fact, as the film abandons its flights of comic body horror whimsy - the title and most of the first 30 minutes of plot are derived from the litany of magical uses that Hank can put Manny to, including water bottle, lighter, and erection-based compass - and starts to embrace the maudlin roots that it initially seemed to be mocking, that it grows increasingly tedious. Sensitive bros expanding on philosophies based on their limited, pop culture-oriented worldviews can work - I will keep watching Richard Linklater movies as long as he keeps making them, and that's pretty much the most reliable element of his filmography - but they're much likelier not to. Indie history is littered with sad, single boys who listen to mopey music and tremulously discuss the fragile beauty of the world, and the more unironically that Swiss Army Man embraces that ethos, the more tiresome it becomes.

In fairness, this all turns out to be very ironic, indeed - Hank is a spectacularly unreliable narrator and POV character, something hinted at from the beginning - but that's at the cost of a third act that I shall not spoil other than to suggest, gently, that it is a mound of steaming bullshit. Honestly, I don't know if it could have been anything else: the best parts of Swiss Army Man are the most plotless, when the cod-epic ironies of the score kicks in and the film is most invested in the mechanics of how Hank lugs Manny around. And especially when Radcliffe (who is better than it should be possible for him to be, given the limits of the role; there's simply a great quality in the back of his voice, which goes from childlike to panicky to sullen and all other sorts of places over the course of the movie) is given goofy, weird dialogue to lance the solemnity of the musings given to his co-star (and while I don't care for Dano as much as Radcliffe, it should be said that he hits exactly the right note of over-delivering his character's pretentious fluff without it seeming like Hank himself is in on the joke). It's a fun hang-out movie, and a fun "what crazy shit will they come up with next?" movie, and fun exercise in building jokes through unexpected shifts in tone and non sequiturs.

All of which means that as soon as the movie decides that it needs things like narrative momentum and, God help us, a point, it trips over its feet and goes sprawling. If the final act is almost totally without any appeal, as I think it is, I can't say that I would have the first clue how to change it: there's no way, really, to resolve this that wouldn't be some combination of too insubstantial for a feature-length film (this is a short film concept, through and through), and too weight and consequential for a film whose strengths are mostly transient. As it is, the ending of Swiss Army Man succeeds in being both, lurching into a profoundly gloomy place that retroactively invalidates most of what made the early parts of the film charming before turning into a soap bubble in the final scene. It's all kind of terrible, honestly, and to what end I cannot say. None of this takes away the essential truth of the movie: it is unique as hell. And it is so fascinatingly messy that even its flaws are interesting. So I'm not prepared to call it a "bad" movie - a horribly compromised, self-destructive one. But no, not bad. Barely.