In writer-director team Joel and Ethan Coen’s first movie, “Blood Simple,” Abby (a very young Frances McDormand) has just left her husband, bilious bar-owner Marty (Dan Hedaya) for bartender Ray (John Getz), the kind of guy Tony Soprano would always wax rhapsodic about as being “the strong, silent, Gary Cooper type.” Suspicious, Marty’s hired Loren (M. Emmet Walsh) a private investigator with a cowboy hat almost as big as his rattletrap VW bug and a sense of humor that, like the movie’s, ranges from blood to novelty girlie torsos with light-up nipples. At first, he just wants to know who his wife is messing around with. Then, he wants them both dead, for $10,000.

The “simple” in the title refers to the tunnel-vision of violence, coined by noir author Dashiell Hammett: “This damned burg’s getting me. If I don’t get away soon I’ll be going blood-simple like the natives.” The Coens were definitely conscious that the movie could, itself, go blood-simple if it focused just on the murder plot. Instead, there’s plenty more to pay attention to, the kind of funny or goofy elements most writers would just scatter like soy protein in a high school cafeteria hamburger, without any sense of texture: Meurice, the Four-Tops-loving bartender whose white Converses you see squeak over the bar when he queues it on the jukebox; the snarky teen-filled makeout pointe where Marty and Loren schedule their crimes; that Ray’s house, the subject of many heated exchanges, is on a dead end, causing everyone who tears off to have to slam on their brakes, turn around and pass by the house again to make their exit. Then, there’s the jilted girlfriend whose story we only ever hear on an answering machine: “She says you’re full of shit and frankly I believe her. And hey, I love you too. Sure. Anyway, you better call me soon because I’m going to South America tonight—you know, Uruguay?” The Coens have a way of tackling such oddball material that they could do a spin-off movie about her, whoever she is, and it would probably be awesome.

After the idea of a murder-for-hire comes out, it obviously can’t go as planned. A crime scene cleanup goes wrong, sparking distrust and miscommunication and greed and “blood simplicity.” But that’s “Die Hard” stuff. Making the psychology work and the characters not seem like too-clean cutouts as everything unravels — that’s the most simple and elegant thing about the movie.

Despite some fading in this DVD version, the cinematography is still amazing for a first movie, panning up over a caricature of a passed out drunk as Patsy Cline’s “Sweet Dreams of You” starts up, the just-on-the-edge-of-consciousness bug zapper and incinerator burning when Marty and Ray confront each other about the affair, the way a Zippo lighter is made visible under a pile of fish, and finally, the way bullets punch six columns of mote-filled light through a cheap wall into a dark room. The Coens see things — like the underside of a sink — that most people never think about.

Most writers and directors could work a lifetime and rightly consider a solid noir like “Blood Simple” to be the pinnacle of their careers. On the scale of the Coens, it’s not their finest work — not just because of McDormand’s belted purple career-girl jumpsuit — though like all their movies, repeat viewings would be worth it. The great thing is that after more than a quarter century of overall improvement, they’re still showing no sign of resting.