Lewis Carroll’s “Alice in Wonderland” is a fairytale about a little girl trying to find her way in a world populated by grotesque, illogical, childish adults. Tim Burton’s film imposes a second identity crisis on the tale, that of a director uncertain of how to proceed.

Is this a remake or a sequel? Comedy or action-fantasy? A kid-friendly Disney picture or a dark, gnarled Burton film? Is it set in Wonderland, Narnia or Willy Wonka world? Even the look of the film is compromised by lukewarm 3D effects applied in postproduction. Indecision haunts every frame. The result is a clattering, hectic spectacle that by the end has run out of inspiration. It’s a home for abandoned ideas.

Commercial considerations seem to have guided the decision to make this film’s Alice a nubile 19-year-old, the better to appeal to the crucial teen market. And so we have needless bookends to the story, opening with a Peter Pan over-the-rooftops-of-London introduction to 6-year-old Alice and her Papa, a visionary merchant with wild dreams of opening up new Pacific trade routes. Alice, troubled by nightmares of a strange underground kingdom, needs reassurance before bed. “You’re bonkers,” he smiles, “all the best people are.”

Thirteen years later, Alice (Mia Wasikowska) is being pushed into an arranged engagement by her widowed Mum (starchy Lindsay Duncan). At a lavish garden reception, the chinless young aristocrat asks for her hand. “I need a moment,” she protests, fleeing the scene and tumbling into a rabbit hole. Down here she encounters the usual Burton aquarium of bizarre creatures: dragons and insects and scales and tails and tendrils, exotic vegetation and foliage and enough gargoyles to protect a hundred cathedrals. The film looks as though a dozen production designers competed with each other to see who could achieve the most outrageous folly. Filigree grows over everything like visual kudzu.

This is Underland, where topsy is turvy and nothing fits. Burton visualizes Carroll’s characters with eccentric flair. Helena Bonham Carter makes a ticklish impact as Her Scarlet Highness. With a bulbous balloon noggin atop a diminutive frame, she’s inflated ego incarnate, and her peevish performance is a delight. As the pallid White Queen, Anne Hathaway is another of Burton’s corpselike lust objects, Snow White on formaldehyde.

Of course the main event is Johnny Depp, a human special effect as the Mad Hatter, with his neon-orange fright wig, ruby-toned rouge and computer-enlarged emerald eyes. He oscillates between eccentricity and insanity, his accent shifting from cockney to Scots while as his wardrobe changes color to reflect his mercurial moods. It’s a clowning Christmas pageant performance, but suited to the part.

Alice is told at every turn she isn’t “the right Alice.” And in truth Alice has a marked lack of personality at first. Wasikowska underplays her character’s wonderment, attributing her experiences to a bad dream. A scroll foretelling the future names her as the champion who will defeat the Red Queen’s dragon, Jabberwocky. Alice doesn’t see it that way; she’s temporarily stranded and will be waking up any minute now.

Two thirds of the film is spent waiting for her to get on with the swordfighting. The tacked-on battle finale entirely misses the point of this Victorian coming-of-age fable. It doesn’t update the story, it shreds it. The producers must think that turning Wonderland into Gondor is how you give audiences their money’s worth.

After Alice drinks a shrinking potion, the Mad Hatter remarks, “You’ve lost your muchness.” If Burton had scaled back the muchness he might not have smothered the lovely fairy tale underneath.