Shane Carruth is more than happy to talk about his remarkable new film “Upstream Color” in substantial detail, poring over its staggered themes and elliptical construction with a discursive chattiness that suggests he, too, is still discovering further possibilities within it. Just don’t ask him for a nutshell synopsis.

“Here’s the thing,” he says breezily, after I ask him if such summarization is even possible with this glistening glass onion of a film, a kind of physiological romantic thriller suffused with surgical sci-fi. “Because that’s something I’ve been so averse to, I’ve tried to craft the marketing in such a way that conveys what’s on the film’s mind. I’m more comfortable with creating trailers and key art that suggest what the film is, that encapsulate and maybe even contextualize it, more than I’d be willing to synopsize it.”

What Carruth refuses to do, many a critic has painstakingly attempted since “Upstream Color” dazzled and flummoxed audiences in equal measure at the Sundance Film Festival in January – the same festival, of course, where Carruth’s equally teasing, genre-melting debut feature “Primer” won the Grand Jury Prize in 2004. The internet is awash with reviews and navigational articles boasting an authoritative interpretation of the film; inevitably, hardly any of them overlap completely.

Two viewings later, I feel neither qualified nor inclined to join the critical code-cracking. There are stray strands of “Upstream Color” that I still find inscrutable, which is not to say I’m not moved by them. Carruth, who also acted as his own writer, cinematographer, composer, co-editor, co-producer and leading man, has fashioned a film that is somehow at once fastidiously technical and emotionally overwhelming; aided by the grandeur of its imagery and sonic design, it’s possible to intuitively understand “Upstream Color” even as the brain is still disentangling the narrative’s dense series of life cycles.

“Many of my favorite films, if someone were to tell me simply what they’re about, I probably wouldn’t be that interested,” Carruth says. “Plot often has so little to do with what’s at the heart of a film. Maybe this is just stubbornness on my part, but if I don’t have to describe it that way, and there’s a way not to, then I want to figure that out.”

It may be interfering with the intended approach path Carruth has laid for first-time viewers to say that “Upstream Color” is a love story, though not before it’s a serene exercise in body horror. The film’s young female protagonist, Kris (Amy Seimetz), is violated with a bio-engineered worm that spawns inside of her; when that biological experiment is countered with another involving pigs, she’s left with no memory of the ordeal – only the trauma. 

She finds solace in a similarly damaged man (played by Carruth himself) who appears to have been absorbed into the same ruling life cycle – it’s here that the film gives itself over almost exclusively to cinematic language as opposed to dialogue. Oh, and there are orchids. Many orchids. Carruth’s right: verbal descriptions, both within the film and about the film itself, don’t quite do the trick.

“I basically needed to strip our central character, Kris, of her personal narrative, to make her a raw nerve and a blank slate,” says Carruth. “I needed her to adopt a new narrative based on potentially the wrong information that she wakes up to, to be affected at a distance by things she couldn’t necessarily speak to. That’s a way into exploring all the things that affect our subjective experience: be it religion or physiology or psychology or pharmaceuticals or ethics or politics systems. All these things come to shape us, or we come to shape them. That was the core of it, so I then came up with a structure around it: this life cycle – of worms, pigs, orchids – to support that.” 

In conceiving the film, the abstract ideas unsurprisingly came to Carruth before the human dynamics did, though the elements ultimately shaped each other: “I knew it was going to be a love story when I started writing the script in earnest. I had been accumulating these ideas, but only as a thought experiment, really. And the more I stripped away these layers of a person’s identity, the more it felt really heartbreaking to me. It’s horrific to find yourself vacant, not certain of anything. Once it registered how much this person would be broken, that lent itself to a romantic premise. And that’s when I fell in love with the story, knowing that would be its heart.” 

Carruth enlisted hot new multi-hyphenate David Lowery (who unveiled his own directorial effort, “Ain’t Them Bodies Saints” alongside “Upstream Color” in January’s Sundance competition) to edit the film with him; a significant collaboration for an artist who is otherwise so self-sufficient. Did Carruth have the film’s splintered narrative planes mapped out beforehand, or did much of it come together in the editing room? 

“This is difficult, because it’s nuanced,” he says with an airy laugh. “A lot of it was known in the writing, but then the visual language came to be, and that in turn affected some of the music I had written. So I had to change that. And then that affected some of the script again. And when Amy [Seimetz] showed up and I saw how effective she was going to be, that meant some of the other filmic elements could step back a little bit. So in the final two weeks before production, things more or less coalesced. 

“But there are always moments when we walk into a room with a Plan A, but there’s something there that’s really interesting that wasn’t there before, and it works better. And first I’ll think, ‘Oh, what a happy accident’ – only to look back and see, no, that was actually in the liner notes. Everything becomes a storm. The part of the film that deals with shared memory is an example where we had such a clear idea by that point of how the film was going to work in terms of editing and camera and performance that we could follow our intuition – it wouldn’t have been any more effective if we’d scripted it that way. I wouldn’t call it improvisational, but it is definitely led by something beyond the page.” 

He is unreserved in his praise for Seimetz, who herself made an acclaimed directorial debut last year with the solemn, “Badlands”-echoing road movie “Sun Don’t Shine.” Carruth describes the experience of working with another actor-director, as opposed to simply an actor, as “like night and day”: “With her being a filmmaker, she could be quite intuitive herself with the story. Her film is so wonderful and lyrical itself; she gets how it works, maybe better than I do. So it was a collaboration, not me instructing her, which made everything a lot easier.” 

Arguably Carruth’s ultimate declaration of independence with “Upstream Color,” meanwhile, was his decision to self-distribute the film in the US, a tactic that he admits has involved “an enormous amount of work and stress, and still the chance that it could fail in some way.” So far, however, it seems to be working: the film is gradually being rolled out to an impressive 50 markets in North America, with cable VOD, DVD and Blu-ray release set for May 7 – a shortened window that bigger distributors might not opt for, but one that makes perfect sense for a film that demands repeat viewings as urgently as this one. 

Carruth’s team even managed to arrange an official Academy screening of the film last week: a significant step for a film that lies a long, long way from standard ideas of Oscar bait. Whether Carruth winds up campaigning or not, he’ll be able to do so on precisely his own terms, just as he’s steered the non-standard marketing of “Upstream Color” to audiences. It’s the latter liberty that he describes as his “number-one motivation” for facing the challenges of self-distribution. 

“There are things we need to change next time around, and we’ll do a better job next time out,” he admits, “but at this point I can’t imagine giving up the ability to craft the context, the way in which the audience receives the work. I wanted to be really earnest about it: I didn’t want to trick anyone into theater, expecting one thing and getting another.” 

Before the film made its Sundance premiere, Carruth set about crafting three trailers that, more than selling the film on story itself, gave potential viewers some idea of how the storytelling would actually work, and how they might be required to absorb it. “The first one was really just selling the idea of being confounding. It showed a lot of the visuals from the film without a lot of context, and suggested that there was something weighty, something detrimental happening to the minds of our characters. And that’s all I wanted to convey; an introduction.” 

“The second one had none of the otherworldly elements: no weird pigs or worms or anything. You might just think this was a drama of a relationship falling apart; it was more focused on the lyrical, the emotionally angsty – which the film also ends up being. And the final trailer mixed those two approaches together, suggesting roughly the execution. And that was the gate, in my mind: it says, ‘Here’s what the film has going on in it. If you’re okay with this, great – we’re going to get along swimmingly.’” He pauses: an audible shrug, his tone still chipper. “If not, maybe we should talk again a couple of years down the road.”