Nobody can take this away from Blue Sky Animation Studios: their new version of Horton Hears a Who! is far and away the best of the decade's three Dr. Seuss adaptations, although neither How the Grinch Stole Christmas - a vile film - nor The Cat in the Hat - a loathsome and vile film - set that bar insurmountably high.

I don't have it in me to criticise those who therefore declare Horton a success (most everybody, to judge from the enthalled packed theater where I saw the film, and the generally positive critical reception), but I'm not at all prepared to go that far. The film is occasionally charming, frequently dull, and terrible just often enough to leave me feeling more dissatisfied than not. Take it for all in all, it's little more than all of the other talking animal CGI cartoons that were unavoidable in 2006 and blissfully absent for most of 2007. There's just enough of the spirit of Theodor Geisel to push the film a notch or two higher than most of its stablemates, but all of the typical ingredients are here: a celebrity-heavy cast composed with an eye towards marketing more than art; copious pop-culture references, several of them pitched miles about the target audience's heads; energetic setpieces that don't really add much of anything to the whole; a pop song sing-along wedged uncomfortably into the film in the most obnoxious way imaginable.

In fairness, some of the tricks that screenwriters Ken Dario and Cinco Paul (a team whose body of work is positively littered with awfulness) use to update the material is clever and maybe even welcome; in particular, replacing Seuss's anti-McCarthyite fable with an atypically subtle anti-Religious Right message borders on smart. The key, for the curious, is when the sour Kangaroo (Carol Burnett) refers to "pouch-schooling" her boy to keep him from learning things she doesn't approve of. Though the pun is acidic, the dog-whistle is unexpectedly sly. Still, like everything else involved in blowing up a perfectly balanced bedtime story into 88 minutes, it tends to get amplified to the point of annoyance.

Along the way, most of the sweet simplicity of Seuss's original is lost; no, not "lost," just hidden behind the bombast. The blame for that lies across a spectrum, from the writers to directors Jimmy Hayward (a Pixar-trained animator; clearly not a Pixar-trained storyteller) and Steve Martino, to the voice of Horton himself: Jim Carrey, veteran of the train wreck that was Ron Howard's adaptation of Grinch. It's not true that everything wrong with the film is Horton's characterisation, but it's probably the biggest single flaw. In the original - and yes, I know you're not supposed to compare films with their source material, but this is Dr. Seuss we're talking about, the 20th century's greatest narrative poet-illustrator - Horton was a simple, driven individual, who naΓ―vely repeated the mantra, "a person's a person, no matter how small," as though that alone could keep the forces of evil at bay and win over even the staunchest ideological enemy, which of course it did. In the movie, Carrey's Horton is a typical example of the comedian's less-disciplined performances, a cavalcade of goofy voices and shaky impersonations. His Henry Kissinger is a particular marvel; marvelous that it found it's way into a 2008 kid's movie, if nothing else. Horton is not here a determined innocent or naΓ―ve prophet, but a wise-cracking show-off, the latest in a long line of Bugs Bunny's underachieving descendants.

In other words, he's the lead character in a CGI movie about animals. It's only objectionable in that it's not remotely Seussian; in fact, in the grand scheme of the genre, at least Horton gets a few honestly amusing lines. That's pretty much the whole movie: relentlessly typical, but a bit better than the median. The copious expansions to the narrative source are all out of Writing Post-Modern Children's Movies 101: we have the twisty father-son relationship between the Mayor Who (Steve Carell, blissfully uninterested in vocal mugging) and his son Jojo, a sarcastic side-kick for Horton, Morton the mouse-thing (Seth Rogen), and lots of little comic vignettes that are wry more than they are witty. There's also a whole lot of narration, delivered by CBS News figure Charles Osgood, and this is objectionable: it's in Seuss's customary meter, and in Seuss's customary rhyming couplets, and the great majority of it is not written by Seuss. This is the equivalent of a Shakespearean film in freshly composed blank verse - "Oh God, you are so sexy, Juliet / I'm gonna bone you right here on the floor" - and it's horrifying in a moral sense, to say nothing of the aesthetics.

As for the animation: well, credit to Blue Sky for not going the Dreamworks route and making all their films look identical. Horton is no Ice Age, though some of that franchise's attempted photorealism can be seen here and there in the jungle backgrounds. Unfortunately, their game attempt at making Seuss's drawings move - thought not remotely as soul-devouring as it was in the live-actions films - is at best a wash. Even at his most detailed, Seuss relied on spare art to carry his words, more like tinted pencil sketches than anything. There is a moment early in Horton when the elephant's imagination renders the Whos in a 2-D style that looks exactly like Seuss's drawings come to life (far more than in Chuck Jones's classic Grinch TV special), and it's the most visually exciting part of the movie. Otherwise, it's all a bit too detailed, to meet the needs of a marketplace dictated primarily by Pixar's frightening precision, and it doesn't feel very Seussish at all. The characters don't really look right, more than anything; I don't just mean that they don't like like the drawings (and really, they don't), but also that they look a whole lot like plasticine figures moving with sinuous fluidity. There are definitely places where this is flat-out horrifying, and unfortunately, most of those places involve Horton himself. Tactile animated characters are fine, but these look like Horton toys acting out the plot.

Ah, well. I'm not the audience for this film. I can only call it as I see it from my mirthless tower of adult intellectualism: it's kind of unsettling to look at, kind of frustrating to listen to, and kind of boring to sit through. But all that "kind of" adds up to "not horrible," and that, I suppose, is more than most children's movies can say.