Jesse Peretz's Our Idiot Brother is the kind of movie that may very well play better on a second viewing, once your expectations have been adjusted and you know what they're going for. It is not, in spite of its broad premise and rather stock characters, a laugh-a-minute comedy; Peretz (and writers David Schisgall and Evgenia Peretz) go for a more muted, low-key affair. Then again, a second look might make all the more apparent the film's central flaw--that those two approaches are fundamentally at odds with each other. It is a good film, due primarily to the skill and pizzazz of its loaded cast. It is not a great film, though, because it doesn't seem sure of exactly what it wants to be.

It is the story of Ned (Paul Rudd), a likable and utterly dim-witted hippie type, always wearing a beatific smile beneath his Jesus beard and hair. In an opening scene of sheer comic perfection, he sells a bag of weed to a uniformed police officer; when he gets out of jail, he finds that he's lost his girlfriend, his home, and his dog (always referred to by his full name, "Willie Nelson"). Adrift, he proceeds to burn his way through the limited goodwill of his three sisters, leaving well intentioned but indisputable emotional wreckage in his wake.

With his stoney denseness and "hey, man" dialogue patterns, Ned is a pretty basic comic type, but he doesn't know that, and Rudd acts like he doesn't either; the actor calls upon his seemingly bottomless repository of charm and plays the character with honesty and integrity. The trouble is, all of the actors are fighting that same battle. These are mostly familiar and rather sitcom-y characters, at least in conception: the cold, career-minded materialistic social-climbing sister (Elizabeth Banks), the overprotective yuppie parent sister (Emily Mortimer), her blowhard documentarian husband (Steve Coogan), the flighty Brooklyn bisexual sister (Zooey Deschanel), and her hipster girlfriend (Rashida Jones).

Of course, a rundown of that cast list indicates that nuances will be found within those broad semi-caricatures; Deschanel, for example, gets past her chracter's surface to find the desperation underneath, while Coogan's angry husband is a perfect vehicle for his patented brand of passive-aggressive hostility. But Peretz and his writers make the fundamental error of taking these broad characters too seriously, too realistically; they should have either created less obvious types, or done the kind of go-for-broke all-in laugher that the film always seems just about ready to become.

Rudd, it should be reiterated, is comic perfection. He gets the two biggest laughs in the movie, though neither of the lines ("Aw, shit" and "Man, I had a feeling about that") are exactly knee-slappers on the page. It is his perfect timing and the way he thinks while he talks that sells them. He also gets to work in some real emotion towards the end, in a family blow-up during a charades game that has enough dimension to ratchet up the entire performance. And for whatever it's worth, he shares a two-scene with Adam Scott that plays like a demo reel for a Scott/Rudd buddy comedy; they get a terrific rhythm going.

Our Idiot Brother is an agreeable picture, full of polite chuckles, but not many of the big laughs we go in looking for. It is a sweet, fizzy little movie, not entirely successful, but certainly not offensive or ill-intentioned. As a showcase for its impressive cast, it does the job. It does, however, have the undeniable feel of a missed opportunity.

Jason lives in New York. He holds an MA in Cultural Reporting and Criticism from NYU.