Goddammit, but I wish A Ghost Story was a masterpiece. It comes real close. The opening half of writer-director David Lowery's 92-minute feature is a marvel and then some, marshaling some highly idiosyncratic cinematography, sound design, and performances in the creation of a breathtakingly good exploration of different forms of existential loneliness. And the second half (almost to the minute; I felt the downshift so powerfully that I was compelled to check the time right there in the theater) is.. kind of the same thing, but also a whole lot not the same thing, and it's easy to see that there's a breed of viewer who'd be hugely jazzed by where this goes, but it's easy to see that such viewers are probably going to be in the minority (I say "probably" because the very self-selecting audience who'd ever end up in A Ghost Story is, admittedly, the kind who'd be likelier to sign off on the second half in all its unexpected bobs and weaves).

So anyway, it's a ghost story, alright, but not the kind that we usually get. It's a glacially slow domestic tragedy without a solitary frightening moment, and when Daniel Hart's score dives in the direction of of a traditional horror movie cue, it feels distinctly like a mildly sarcastic joke more than anything. The situation is this: a man (Casey Affleck) and woman (Rooney Mara) live together in a house that would seem to be haunted. Stuff goes bump in the night, at least. Without being able to quite put our finger on why, it becomes clear that she's not as happy with their current situation as he is, but in the very near future it won't matter: he dies in a car crash. At the hospital, right after she says her goodbyes to the body, he returns as a ghost - the old-fashioned "bedsheet with holes cut for the eyes" kind of ghost, no less - and stops before entering The Light. Instead, he goes back to their house, and watches in silent isolation as she mourns in silent isolation.

It doesn't sound like much because it isn't much: what we have here is a case of some real hot and heavy minimalism. It's the purest example of slow cinema I've seen in an American film since I don't know when, spending minutes at a time on very nearly nothing at all but watching hushed people barely acting. If I were to tell you that the most riveting, powerful,  enormously important part of the movie is a shot of the woman sitting down on the kitchen floor to eat a whole chocolate pie - the pie filling, at least, she seems to leave the crust behind - while the ghost hangs out in the background of the shot, not moving as he watches her, and that this shot goes on for what feels like a solid four minutes (this one I did not check the time, I was much too attracted by the onscreen action. Or "action", anyway), I think I will have give you a sense of what the film is, and why it is exciting to certain people, and what kind of viewer those people are. I would not care to spoil the end of the pie-eating shot, but it is, in context, as startling and intense as anything in the year's noisiest blockbusters.

Slow cinema's not for everybody, of course, but A Ghost Story is slow cinema at its best, using it not just for some nameless ideal of "let us now make Film Art", but to put across an extremely clear, almost viscerally potent emotional state. Basically, this is a film about the crushing loneliness of isolation, felt both by the widowed woman (I assume, the film never tells us that they're married, and I don't guess that it matters) and the ghost, in two very different ways. It is about that epic-sized awful feeling when you realise that, in fact, you could spend the next five minutes sitting and doing nothing, and there'd be nobody to notice that you had done so, or even care. For the woman, this manifests in, for one, devouring whole pies in a pitiable act of childish self-destruction. For the ghost, this manifests in falling out of any sense of time whatsoever.

And here's where we really get interesting, and to the heart of what makes A Ghost Story so extremely wonderful in the early going. The reason for focusing on the ghost and not the living woman is that she can grow, change, heal, and move on. He can't. He's stuck in one place and one moment in time, and in one emotional state; he is no longer part of the human flow of life, and that's what A Ghost Story attempts to dramatise in an extremely cool way. Basically, the film itself loses track of time, using low-fi techniques to show how the ghost's experience of chronology lurches ahead, condensing moments into a single event, so that we might see the woman bend down and then cut to a shot of her standing up days or weeks later. In one of the few "look at me, I'm a special effect!" moments in the picture, the ghost watches as the woman leaves the house three times in one uninterrupted shot.

It's beautiful and horrifying all together, a vivid rendering in purely cinematic idiom of losing any connection to the basic ebb and flow of life, rendering time itself from a completely non-human perspective. Coupled with the extraordinary wide shots that Lowery and cinematography Andrew Droz Palermo favor in their full-frame compositions - it looks somewhat like the film was shot to be matted but never was, leaving enormous gulfs of empty space at the top and bottom of the image (that's not what actually happened, just what it looks like - this was clearly all done deliberately and with intention) - and the effect is of something that feels very indifferent to human experience and perspective, with the character occupying scared, tiny little spaces in the center of the frame.

And then... I don't want to say. Not withstanding both that star rating and that "bang for your buck" score, it's a film I'd really like to urge people to see; if the description of the pie-eating scene didn't turn you off, then I'm fairly sure you'd dig it, whoever you are and whatever your tastes. But the thing is, it shits the bed, messily. It's not for want of ambition, at least: having cribbed from the Terrence Malick playbook with Ain't Them Bodies Saints in 2013, Lowery is now essentially giving us his version of The Tree of Life, in which the universe-scale totality of existence and time are re-fashioned in the scale of human (and ghost-human) consciousness, without losing the sense that it is infinitely larger than all the existence of all the humans who ever were or will be. And that part is cool. But it's not executed with the same enormous precision of the first half, nor with the same emotional tenderness - the ghost (sometimes played by Affleck, sometimes by art director David Pink - in interviews, Lowery has implied that it's more the latter than the former) turns out to be a surprisingly sympathetic figure, the cock of his head as he considers the woman with his dark eye sockets proving almost impossibly subtle and sweet. But there comes a time when he turns into an almost entirely passive observer as Lowery's sense of cosmic grandeur takes center stage. And even that would maybe be tolerable if Lowery didn't go ahead and butcher the momentum and texture of his almost wordless depiction of loss and love with a painfully explicit monologue setting out everything that has happened and will happen in unimaginatively small prose (but I'll say this, it's a real treat to see Will Oldham crop up to do anything, even if it's to ruin a great movie).

It's all very neat and very head-trippy and whatever, but I frankly don't give a shit. The first half of the movie doesn't need to be head-trippy: it's too powerful in its emotions and breathtaking in its combination of absolute stillness and manic fast-paced time jumping. Re-imagine A Ghost Story as a 45-minute featurette, or transform the second half into a 10-minute coda, and you have one of 2017's absolute  best. Leave it the way it is, and you have one of 2017's most heartbreaking misfires: a film whose greatness is too profound to say that it can be safely ignored, and whose errors very nearly swamp all of that greatness in dipshit stoner philosophy.