Peter Jackson’s Tolkien tribute took a knee-bruising stumble with “The Hobbit,” a droopy piece of work that was less action and adventure than a prologue that got the three-part story moving with a limp. What a relief to say that Jackson, the maker of the smashing “Lord of the Rings” trilogy, has found his groove again. “The Desolation of Smaug” is a rip-roaring wizards and lizards escapade that delivers a full quota of thrills while remaining true to the lighthearted spirit of the source material.

Jackson gives himself a winking cameo in the first frames of the movie, looking into the camera and chomping a carrot like Bugs Bunny. He captures the spirit of Looney Tunes exuberance for most of the next 2¾ hours, in a confident film that has more surges than sags. It’s not just the snazzy effects technology that sings here, it’s the storytelling.

Every fan knows the tale: Timid Hobbit Bilbo Baggins (the supernaturally expressive Martin Freeman) has been pressed into aiding 13 dwarves on their expedition to reclaim their lost homeland. On the side of good are the benevolent wizard Gandalf (Ian McKellen) and dwarf warrior Thorin Oakenshield (Richard Armitage). In the opposite corner are the malevolent Master of Laketown (Stephen Fry, deliciously pompous) and the fearsome dragon Smaug (voiced by Benedict Cumberbatch), who sleeps cuddled up beneath a vast blanket of the dwarves’ gold coins. Also on hand, and somewhat conflicted about aiding the wee folk on their quest, are the elves Legolas (Orlando Bloom) and Tauriel (Evangeline Lilly).

This is not the place for the uninitiated to enter Jackson’s Tolkien universe, clearly. If you have a grasp of the iconic characters, however, it’s a wild toboggan ride. Marvelous scenes, stunning images and thrilling moments whip past in a delicious blur. I recommend it unreservedly, except to arachnophobes. An extended passage with giant woodland spiders lunging after Bilbo and his dwarf platoon might send them screaming for the exits.

The film fizzes with excitement. Hideous humanoid Orcs ambush our brave little heroes at every turn, and each breakneck skirmish has its own logic. At one juncture the good guys bob along white-water rapids in barrels while their adversaries shoot arrows and slash at them with axes. The battle continues on a second front as a couple of elves attack the attackers. The sequence is a zesty brew of thrills and gleeful carnage, high drama and low comedy. The Orcs are so brutish you can’t help laughing when they’re knocked off cleverly. Bloom and Lilly could have promising post-“Hobbit” careers in ninja movies.

What an eye, what an expansive imagination Jackson has. Every locale has an eccentric, richly individualized texture. His use of locations is breathtaking and evocative. Look at his actors striving up a mountainside and you’re persuaded that they actually are on an early, raw draft of Earth.

(Critics were shown the film in the traditional 24-frames-per-second rate, not the 48-fps form which Jackson inexplicably champions, and which will be available in select showings. Given how overbright and unnatural that presentation made “The Hobbit” look, I recommend you seek out standard-speed screenings.)

The sets are designed with a positively Gothic overabundance of detail; every corner of the frame is packed with visual surprises. How many thousands of craftsmen did it take to weather each cedar shingle and warp each plank sidewalk in Laketown? The establishing shot of Smaug’s vast treasure storehouse even has a fleeting image of a child’s gilded sled, a sly tribute to “Citizen Kane.” Fanboys and film geeks both get full service here.

The film deploys its big effects to great advantage, too. A sorcerer’s showdown between Gandalf and the Necromancer, a dark, smoke-like wraith, becomes a duel between brilliant light and smothering murk. It’s the essence of magic, rousingly realized.

For all the film’s audiovisual dazzle, it’s not a riot of effects without a stabilizing core. The actors never feel like also-rans to the special effects. There’s a herd of characters, each sharply drawn.

Freeman’s Bilbo begins to emerge as a courageous adventurer here, gaining a new layer of confidence in every scene. McKellen never hikes an eyebrow at the material, playing his pointy-hatted spell caster with the same consummate commitment he brings to Lear onstage. Cumberbatch, as the greedy dragon, gives his dialogue a baleful resonance.

A cliffhanger provides a satisfying finish to this chapter, a bombastic battle royal between the wee folk and the flying serpent, and sets up what promises to be a thrilling conclusion next December. Could an editor with a machete chop out an acre or so of story? Sure, but at this point the epic scale is part of the deal. Viewers with limited attention spans or weak bladders need not apply. For me, it ended too soon.