It takes an age before Johnny Depp shows his face in "Pirates of the Caribbean: At World's End," and when he does, it's the tip of his nose that looms into screen left, eventually succeeded by a flaring nostril.

I doubt there's been a larger, longer close-up of a proboscis this side of "Seabiscuit," and there's no rhyme or reason for it, really. But our indulgence is rewarded when not one, not two, but an entire crew of digital Depps bounce into view, flouncing and flailing for all they are worth. One even lays an egg.

Depp's Captain Jack Sparrow, you may recall (spoiler!), bought a one-way ticket to Davy Jones's Locker when he went down with his ship at the end of the last film, "Dead Man's Chest." Not that death is a terminal condition in this series; before "At World's End" is through, most of the cast will have perished at least once and returned to the fray.

For Sparrow, perdition is to be marooned on the Black Pearl in the middle of a desert without a whisper of a breeze. The doldrums. It's enough to drive a buccaneer to distraction.

He's not the only one.

The entire franchise seems on the verge of collapse, propelled to construct ever more grandiose flights of fancy. Without those sequences, there would be nothing there -- but a movie cannot exist on rollick alone (not by the second sequel anyway). I kept flashing to the image of a doomed mariner furiously bailing out his boat as it sinks inexorably beneath the waves.

The problem is not so much that the energy -- or the invention -- flags. But the audience may. Screenwriters Ted Elliott and Terry Rossio have been working overtime. Having fabricated an entire supernatural pirate mythology from odds and ends (a theme park here, a Flying Dutchman there), they now feel duty-bound to lay it all out for us as they go.

And the more that is explained, the murkier everything gets.

"World's End" features so many detailed negotiations between charlatans with obscure cross-purposes you head for the exit more confused than when you went in.

Still, it's all as splashy as $250 million can buy, and on occasion the CGI guys conjure something akin to poetry: for example, a sampan gliding through a vast arctic cave, then emerging like a spaceship into an inky black sea reflecting the stars above ("You have to be lost to find a place that's never been found," rationalizes Capt. Barbossa, once again played by Geoffrey Rush).

Or the Black Pearl surfing through the sand on the back of a million crustaceans. Or the climactic sea battle on the cusp of an oceanic whirlpool. Or its wonderful character creations, notably Davy Jones himself (again by the terrific Bill Nighy).

We critics routinely shortchange such wonders, but blockbusters thrive on spectacle, and any movie that can produce a 50-foot woman almost as an afterthought has no worries on that score.

At the same time, it's easier to warm to the vaudevillian Hope-and-Crosby-style comedy director Gore Verbinski keeps trying to smuggle in under the radar, in dozens of throwaway sight gags, madcap verbal non-sequiturs, and slapstick set pieces. Depp is his principal ally, of course, the agent of chaos swanning his way through the heart of the whole shebang.

It's really too bad this wonderful anarchy is swamped by the movie's noisy inconsequence. Fully an hour too long -- 2 3/4 hours! -- and emotionally frigid, "Pirates" is scuppered by nothing so much as its own inflated self-importance.