Mandy is a good example of how not to make an homage to Stephen King, John Carpenter and other dark ‘80s pop culture icons.

While director Panos Cosmatos has pulpier goals than, say, Stranger Things, his overlong tribute to the era frequently loses its focus and steadily dilutes the visually rapturous, 80-minute ballet of violence at its core.

Set in 1983 amidst woods that resemble the Pacific Northwest, the film centers on timber cutter Red (Nicolas Cage) and his titular shop clerk girlfriend (Andrea Riseborough, The Death of Stalin), about whom little is known beyond their deep love for each other.

That connection is established in a sluggish first hour that would be intolerable without the late Jóhann Jóhannsson’s synth score. Occasional weird imagery, much of it imbued with a Martian red glow lifted from the past two Nicolas Winding Refn films, provides momentary boosts and giant King-esque text fills the screen to announce a handful of chapters, but neither detail adds up to much beyond atmospheric window dressing.

The plot at last kicks in when cult leader Jeremiah (Linus Roache, Batman Begins) takes a liking to Mandy and charges his followers to acquire her through the use of a mystical horn that summons bizarre biker gang creatures. Through such steps intriguingly straddle the line between reality and fantasy, the leather-clad mercenaries are probably just punks on LSD doing vocal impersonations of Frank the rabbit from Donnie Darko.

Once the deed is done and things don’t turn out well for our heroes, Mandy comes closest to realizing its potential in a second half revenge fantasy with Cage in crazy, overacting mode.

Drenched in blood, his eyes wild and his body an unstoppable killing machine wielding a crazy battle axe that he forged himself — in slow motion, no less — Red’s generally entertaining rampage is fortified by brief, random animated clips, fever dreams and related insanity that nearly arrive too late to be enjoyed.

Considering the players, their circumstances and the intricate way they’re filmed, anything goes and the gore is justifiable, unlike in the recent, reality-rooted Peppermint. But while the end result will likely have midnight movie fans clamoring for more, viewers still groggy from the laboriously build-up won’t want to revisit this dimension anytime soon.

Grade: C-plus. Not rated, but with strong language, bloody violence, nudity and drug use. Starts Sept. 14 at Biltmore Grande and Grail Moviehouse

(Photo: RLJ Entertainment)