In the “Class of …” series, Nick Rogers takes a monthly look back at films celebrating either their 20th or 30th anniversary of initial release this year — six from 1986 and seven from 1996 (the extra in December’s double-feature column). The rules: No Oscar nominees and no films among either year’s top-10 grossers.

Many writers have invoked Romeo and Juliet talking about co-writer / director Alex Cox’s Sid and Nancy. It follows the burn-bright, fade-fast coupling and squalid deaths of Sid Vicious, the British-born Sex Pistols bassist-vocalist who embodied a stronger attitude for punk than an aptitude for performing it, and Nancy Spungen, an American who supplicated before an altar of drug abuse until it became the site of her sacrifice with Sid at her side.

Correlating these twentysomethings with the Capulets or mixing them up with the Montagues suggests the romanticized notion that they died in love and in pursuit of a far nobler principle of punk ideology. That’s quite far off the mark in describing what was, in reality, a far more symbiotically parasitic connection in which Vicious and Spungen worshipped the high more than each other.

If any human feeling existed between them, it was empathy through extremity. Early on, Vicious follows Spungen outside a London bar after a brute accosts her. “That looks like it hurts,” he says. “So does this,” slamming his forehead full bore into a brick wall. Not for nothing does Cox foreground someone crashing a moving toy car into another immobile toy car as they consummate their relationship — he the irresistible force to her immovable object. Whatever brief flashes of domesticity Vicious and Spungen shared quickly dovetailed into dependency, despondency and domestic violence from both of them.

Immortalized on its poster, one of the 1986 film’s iconic scenes sees Vicious and Spungen kissing deeply in an alleyway as garbage falls from above. Cox frames them not as a contrast of comparative light in the world but virtually indiscernible from the detritus descending on their heads and all around them.

Instead, Cox (coming off 1984’s cult hit Repo Man) and cinematographer Roger Deakins (who would become a cinematographic heavyweight) conjure something like a macabre mounting of A Midsummer Night’s Dream in which Oberon and Titania clash with a fury that seems to scorch the very landscape around them and heroin becomes their Puck — an uncontrollable chaos agent from whose meddling no happy ending can be salvaged.

Rock ‘n’ roll historians have taken issue with Cox and co-writer Abbe Wool’s depiction of Spungen’s death and the depths of despair to which she and Vicious sunk. Among conflicting theories about who delivered the single fatal stab wound to Spungen’s abdomen on October 12, 1978, Cox and Wool base their reenactment on Vicious’s apparent statement that “I stabbed her but I never meant to kill her.”

Here, Vicious accidentally pierces Spungen’s flesh during a fight over a suicide pact on which he reneged and, in a heroin stupor, passes out before realizing how deep the wound went. (Gary Oldman and Chloe Webb, playing the title characters, improvised their dialogue based on interviews and research material.) Vicious was formally charged with Spungen’s murder but overdosed on heroin four months later while out on bail, allegedly with a suicide note in his pocket.

Largely based on an epilogue that features a hallucinatory reunion of Vicious and Spungen, John Lydon (aka Johnny Rotten, Vicious’s Sex Pistols bandmate) vocally criticized the film as “the lowest form of life,” the work of a “bastard” who missed the punk rock era, a vision that was “someone else’s fucking fantasy” and an unrepentant celebration of heroin addiction. (There’s clearly little love lost from Cox, who depicts Lydon as a belching, farting pig who swigs champagne and scarfs down baked beans.)

Cox has countered that claim by saying he sought to deliver an anti-drug statement that forestalled portrayals of Vicious and Spungen as “real exemplars of punk” rather than “sold-out traitors of it” — a film that might glamorize their deaths as a culturally resonant middle finger to the establishment rather than a degrading, drug-addled waste. Indeed, that scene feels less like souls’ true matches fused for eternity … more like a waystation between Vicious’s final fantasy of getting clean and rehabilitating (although to what end the film suggests nothing) and his last, willful response to Spungen’s siren call (not to mention a sort of symbolic torch passing to another musical genre through his dance with the kids).

So, too, do the film’s opening moments — an audio swirl of police-band communication pertinent to Spungen’s murder — support Cox’s thesis that Vicious and Spungen ultimately were reduced to nothing more than anonymous chatter. It’s also a bit emblematic of the film’s biggest flaw — a first act sacrificing narrative clarity and symbolic context for a somewhat blurry rush toward the back half’s inevitability. So quick is “Sid and Nancy” to offer up a preface featuring violent aftermath, and cycle us back to the thick of the downward spiral, that it feels not exploitative per se but a tad too lusty for blood it must spill.

There’s no mention of Spungen’s teen years — an attempted suicide at age 14, a schizophrenia diagnosis at 15 and a brief spot of academic success that saw her accepted to college in Colorado at age 16 before an eventual expulsion. Only in casual passing are her exploits in the ’70s New York rock ‘n’ roll scene referenced, in which she was, for some time, a prostitute. Not only would it explain her ability to, as Vicious’s manager, book him solo gigs after they exile themselves to the Chelsea (where Spungen died), but it would underscore the marrow-deep pain of her final entreaty to end it all. (“I’m not blind,” she tells Vicious minutes before her stabbing. “I see everything. You’ll never get straight.”)

Webb fashions a believably grueling mask of desperation and despair as Spungen. But the script portrays her as otherwise so incompetent, insolent and impulsively violent that we lack a full measure of what she may have squandered. Too often, she exists as a tarnished reflection of Vicious’s punk-star light; “never trust a junkie,” she tells him early in a scene played like foreshadowing that he, an as-yet-clean-of-heroin guy, won’t heed, rather than the excuse on which she has chosen to fall back.

More to the point of musical biopic business, the blink-and-miss-it nature of the Sex Pistols themselves, or Vicious’s short tenure therein, is somewhat cluttered. The British punks lasted only three years, released one studio album (on which Vicious barely played bass, having undergone treatment for drug-related hepatitis), and disbanded before the 1980s arrived. For all the movie informs us, the Pistols have been punk-scene mainstays and Vicious a formative member (when he was actually a replacement). Recognizing the movie isn’t, and shouldn’t be, about the band more than two people, added context could still prop up Vicious’s end of the tale — an attraction to ephemeral enterprises that he eventually applied to life itself.

Although there is little skin on Vicious (after a pound-purging diet of steamed fish and melons that briefly landed Oldman in a hospital), Oldman disappears beneath it, depicting a man whose constant movement suggests equilibrium at odds with every one of the world’s immutably scientific laws. It’s a role Oldman almost didn’t take — rejecting it twice, first claiming a lack of awareness or interest in the punk scene and asserting the theater’s superiority until his agent allegedly intervened. He later said he “did not play Sid Vicious very well”; while a flashy breakout role, it is admittedly bereft of the ragged, or rancid, humanity he bestowed on later hot-headed powder kegs real or imagined.

In particular, Oldman’s note-perfect take on Vicious’s cover of Frank Sinatra’s “My Way” — depicted here in a simulacrum of a film project on which the Sex Pistols were working — propels a musical moment that feels like a brown-acid bath of Busby Berkeley and the burgeoning MTV aesthetic.

Although tactfully less conscious of making the film feel cool than in Repo Man, Cox suffuses Sid and Nancy with visuals that are, by turns, surreal, subtle, specific and spine-chilling.

He constantly plants Vicious and Rotten as sore-thumb outliers in the way of “veddy British” institutions like mounted policemen, double-decker buses or pub geezers – evoking a similarly cultural and generational gap as the rougher moments of Saturday Night Fever (down to Vicious worrying about someone touching his hair). In one haunting moment, Vicious and Spungen saunter through a police siege simply because they seem to summon no resistance, perhaps too chemically conked out to do so.

In one rare bit of levity, a shot match-cuts from Sid retreating into the door of pub during a nighttime downpour and emerging in pristine morning light from another. Mosh pits form in front of bands with the sudden descent of unforeseen storm fronts. Even the asses-to-elbows slumber of punk feels specific during a sleepover that crams what appears to be more than a dozen people on the floor of a studio flat.

Although Sid and Nancy lingers little on fateful American tours for either the Sex Pistols or Vicious as a solo act, Cox nevertheless envisions these journeys as a monument to movement for people to whom stillness was anathema. It’s introduced with a bizarre convoy of bikers and tour buses speeding down a sizzling desert highway, flanked by a low-flying helicopter (for the Pistols tour), and a similar barreling through desolation as solo-show crowds dwindle to nil but Vicious rushes headlong toward oblivion. By then, it’s less about art or attitude, more a regimen of resignation to ride life out until it simply ceases.

As Vicious and Spungen’s existence, and the movie, near its end, all that noise, movement and edge leech out alongside its palette, Cox and Deakins slowly draining off color into a nigh-monochromatic mush by the final moments. (Oldman’s face looks as gray as the coat of the cop interrogating him, one result of a compromise between filmmakers who sought to shoot in black-and-white and investors who balked at the idea.) So aggressive is Sid and Nancy’s emotionally apocalyptic, physically discomforting feel that it throws us in their headspace, unable to discern fetid reality from dark hallucination.

Even if Sid and Nancy doesn’t quite represent the imperfect perfection in which punk music so often traffics, Cox’s confident visual symbolism and Webb and Oldman’s performances grant it piercing volume and knotty shape. Perhaps Sid and Nancy more cleanly and soberly symbolizes another punk tenet: Sell out to nothing that would so easily enchant, enslave and exterminate you without blinking.