Peter Jackson’s 500-pound vision exceeds his $207-million budgetary grasp occasionally in his epic take on King Kong — mostly whenever the great ape’s not around.

Kong’s isolation as the dominant animal on Skull Island leads to insecurity, boredom, disdain, anger — all soothed by the unlikely understanding of Ann Darrow (Naomi Watts), an actress who knows a thing or two about the bum hand of fate.

Sure, it’s impressive to watch a big, angry monkey upend foliage like a Tennessee Williams character would furniture. But Kong is a fighter with unquestionable issues, emotions and power. He’s identifiably human, but also frighteningly animal. This computer-generated creation is an exceptionally expressive effect that grabs both the throat and the heart.

Actor Andy Serkis provided the same actorly basis for Kong as he did for Gollum in Jackson’s The Lord of the Rings films; their work here, along with the visual-effects crew, sets an unmatchable standard for the medium that demands to be seen on the largest screen possible.

It’s unmatchable because the movie trots out a parade of other computer creatures that pale in comparison — dinosaurs, gigantic beetles and nasty, slimy, sharp-toothed worms that like to suck on their prey. (That last monster, though, does provide a horrific, unsettling end to one of the film’s supporting characters.)

A brontosaurus stampede is filled with too-frantic editing and digital clutter, as is Kong’s display of physical prowess when taking on not one, not two, but three T-Rexes at once. The action is leaner, crisper and more brutish when Kong fights one antagonist — such as he does toward the end of the T-Rex sequence as the brawl continues on a set of vines.

Giving Kong a Smackdown-style card of villains seems even more unnecessary given the film’s last act — the beast’s majestic, mind-blowing and flawless solo rampage through New York City. Whether apocalyptically destroying a theater, discovering snow for the first time or making his perilous climb atop the Empire State Building, Kong’s final hour also is the film’s finest.

At an unnecessary three hours, the takes a while to find its sea legs, trying to drum up the same hardscrabble beats of Depression-era squalor as Cinderella Man. It doesn’t quite get there.

Not surprisingly, the movie is more in tune with the passion and madness of filmmaking, embodied by hearty helpings of Heart of Darkness symbolism and a surprisingly dark turn by Jack Black as director Carl Denham. (Think Paul Reiser’s character from Aliens, always trying to turn a profit.)

Threatened with a cutoff of studio funds for his latest creature feature and without a leading lady, Denham hijacks his footage and hightails it for the New York docks. There, a crusty crew awaits to sail him and his filmmakers to what they’ve been told is a Singaporean film shoot.

Along the way, Denham picks up down-on-her-luck vaudevillian Ann to play the lead and hijacks harried playwright Jack Driscoll (Adrien Brody, kicking digital butt Brendan Fraser style) to provide him a suitable script. Ann and Jack fall in love, perhaps as convincingly as is possible in a three-hour movie about a gorilla.

Mid-voyage, Denham reveals to everyone that they’re really headed for the mysterious Skull Island — a location on a treasure map (source never revealed) that Jackson films the first mention of so as to suggest it’s the SCARIEST PLACE EVER. A foggy run aground tunes the violins for the symphony of destruction that is to come. Surviving the truly grotesque, demonic cult of dead-eyed Skull Island natives is but the first of the film and boat crew’s problems.

When they kidnap Ann and offer her as a sacrifice to the mighty Kong, Jack battles the island’s creepy crawlies to save her and Denham gets the idea that live theater might trump movies after all — especially if Kong could be the star of the show.

If Jack and Ann aren’t quite the convincing couple, Ann and Kong certainly are. When all escape attempts fail, she entertains. It turns out that Kong is a sucker for slapstick in a sensible scene showing a human appeasing the ape in a non-meal manner.

Ann and Kong’s communication with one hand gesture sets up a particularly heartbreaking moment in a transfixing climax that balances spectacle with intimacy and violence with restraint. It’s a stupendous close to a breathlessly paced film that could have been an all-time great had Jackson and company kept their focus more squarely on the title character.