It’s not every horror movie that opens by killing off future Oscar winners Laura Dern and George Clooney…and Charlie Sheen. And there can’t be many that climax with a godawful but epic imitation ’80s synth pop concert and big explosions triggered by or aimed at one gigantic animatronic grizzly bear.

And if there is such a film, there’s no way it can stay buried forever, unfinished. Because Oscar winner Louise Fletcher (“One Flew Over the Cuckoo’s Nest”) is also in “Grizzly II: Revenge.” So are John Rhys-Davies, Deborah Foreman (“Valley Girl”), Deborah Raffin and Brits Ian McNeice and Timothy Spall.

The story of this grand debacle, a 1983 film that dropped into limbo before it was finished, has been told elsewhere. But now, at long last, we’ve got a cut that isn’t just consigned to bootlegs and film festivals. “Grizzly II” is here, albeit in truncated form (it ends in an abrupt flurry of editing-can’t-hide-this nonsense).

It’s a bear’s “revenge” sequel that doesn’t really connect to the 1976 drive-in sleeper hit that spawned it. But seriously, that’s the least of its issues.

A cult film and artifact from an age when pop was bad, Europop was worse and nature at the movies was at its most terrifying, putting it together for our viewing pleasure is almost an act of comeuppance for a whole lot of now-big-names.

A whole lot of folks took a paycheck and a vacation behind the still-standing Iron Curtain (Budapest, Hungary and environs) for a movie I’m sure Clooney, Dern, Fletcher and a few others were hoping would never see the light of day.

Charlie Sheen? He wouldn’t give a rip. And John Rhys-Davies, of the Indiana Jones and Hobbit movies? He’s bloody hilarious in it and almost worth the price of admission.

Bear gall-bladder poachers are a big problem in Summit National Park where Liberty Bell transfer and city slicker Nick (Steve Inwood) is now top ranger. The opening scene has a camo-clad goon kill a bear cub on park land, enraging Mama Bear. That great big bear starts her rampage, and in a flash the biggest names of all are dispatched long before “Citizen Ruth,” “Three Kings” or “Platoon” made them movie stars.

But the boss (Fletcher) has planned this big money-making rock show on park land, and doesn’t want to know about grizzlies. The show must go on.

“You have to deal with it, and don’t talk to the press!”

Nick teams up with the “bear management” specialist (Deborah Raffin of TV’s “7th Heaven”), who is all about “tranquilizing” the bear, who had to witness its cub butchered by poachers, after all. And the quartet of hunters continue to sneak around to find bears to shoot for Chinese folk medicine buyers, even though this quartet was a quintet just the day before, another early bear revenge killing.

The rangers must “call in Bouchard,” the baddest, best grizzly hunter this side of the Iron Curtain…uh Rockies.

“I yam feenished with grizzlies, monsieur,” Rhys-Davies purrs, a great bear of a man himself, picking up a tree he just chopped down, all set to save this movie with his bare hands. But Bouchard is going to take some convincing. It’s just that this is one BIG bear.

“You ain’t nev-air SEEN no beeg grizzly, Miss Bear Management!”

It’s all kind of like that, with Rhys-Davies making another argument for an honorary Oscar, lending the film what little camp value it can claim.

The rest? The bear special effect, the bizarre, bloated and not-quite-sound-synced concert sequences (which pad the running time, because that’s the footage that survived) and the mostly-off-camera killings don’t add up to much that would pass muster in a modern horror spectacle.

“Grizzly II” never comes close to “so bad its good,” although there are laughs at how bad it actually is, here and there.

Just keep your eyes peeled for VERY young character actor legends in the making Timothy Spall and Ian McNeice and your ears braced for 70 minutes of synthesizer score.

Because they don’t make’em like this any more. Thank God.

MPA Rating: unrated, violence, profanity

Cast: Steven Inwood, Deborah Raffin, Louise Fletcher, Dick Anthony Williams, Deborah Foreman, Timothy Spall, Ian McNeice and John Rhys-Davies — with George Clooney, Laura Dern and Charlie Sheen

Credits: Directed by André Szöts, script by Joan McCall and David Sheldon. A Gravitas Ventures release.

Running time: 1:14