The problem with success is that it builds upon itself like sentient Lego bricks, continuing skyward until eventually, one pillar looks a bit ugly, or a awkward arrangement of pieces is necessary to continue. When this happens, although progress is made, the surveying crowd can't help but raise an eyebrow and wonder what's the matter, despite the continued ascension.

"Up" is a film that, while perfectly enjoyable and well worth the time spent in the theater in front of a cluster of children asking, "What's going on?" with hissed parental replies, lacks the sort of continuous brilliance that marks Pixar's best films. Every time a Pixar movie is about to land in theaters, the media goes ga-ga over their track record, ranking the films  on their credentials, lambasting "Cars" for its startling mediocrity and now hailing "Wall-E" as the studio's tour-de-force. "Up" is best compared to a previous Pixar film, "Monsters Inc.," which although nice, didn't stun anyone.

Watching "Up" as it jerks back and forth between sublimely effective sequences of efficiently condescending, remarkable heartbreaking reality and the haste with which it wants to run away from such sobering moments and throw dogs into goofy airplanes makes me wonder if Pixar was fighting with one arm tied behind its back. It's not that the characters weren't mostly enjoyable, Carl Fredricksen is a wonderful old geezer and Dug obviously steals scenes. It's just that the film rushes away from character interaction and obviously chomps at the bit to leap headlong into a uninteresting conflict between Carl and his childhood adventuring hero.

There's certainly depth to be had in the story of a widower who travels out of a long-seated obligation to fulfil what he thought was his wife's lifelong dream, but that all falls to the background once Carl and his mildly obnoxious companion Russell find their way to Paradise Falls in what could have been the least interesting travel sequence ever. Referring back to the reference to tied arms, "Up" is conflicted between having the same consistent feel of "real cinema" that elevates Brad Bird's films and the likes of "Wall-E" and catering to younger audiences a la "Monsters Inc." and "Cars."

This certainly isn't to disparage "Up" at all, throughout its running time you'll be amused, your eyes may water a bit, but you probably won't be walking out of the film in awe of its deft production and composition. It'll be another cherry on Pixar's sundae to be sure, but it begs the question, "Just how much longer can Pixar make films that have the same mix of maturity and childlike wonder before it begins to devolve into self-parody and redundancy?" Parts of "Up" were undoubtedly tied directly to "Monsters Inc.," both of which shared the same director and both of which follow pretty much the exact same story arc.

Pixar deserves applause for "Up," it's a great film, but what I would like to see (and given their announced production schedule, this won't be coming any time soon) is Pixar tackle a project in the same way that Brad Bird does (and I'm separating both of his films he made with Pixar from the "Pixar" label, since they're unmistakeably his), something lofty and uncompromisingly geared toward fine cinema, as opposed to trying to have the best of both worlds, the childish and the critical. Though I've always greatly enjoyed Pixar films, it's hard to see them further perfecting the formula from "Wall-E." Let's see Pixar take a big, bold leap, let's see them revolutionize mature animated works in the ways that foreign animators often do.

The characters in "Up" may soar amongst the clouds, but the film itself merely stands in place as an amusing and sometimes touching piece of work that aspires to be little else than what we expect Pixar films to be.