After two likable hit comedies, The 40 Year Old Virgin and Knocked Up, writer-director Judd Apatow goes the serious route with Funny People. The results are disastrous.

The film’s protagonist is a comic named George Simmons (Adam Sandler) who’s estranged from his family and has no close friends. His romantic life has been restricted to one-night stands since he lost the only woman he’s ever loved by cheating on her. When George discovers that he’s dying of leukemia, he keeps the news from everyone he knows. His only confidant is Ira (Seth Rogen), a struggling young comedian whose set he catches at the L.A. comedy club The Improv.

Initially George hires Ira to write jokes for him, but Ira quickly becomes George’s personal assistant and finds himself shouldering George’s emotional burden. Ira doesn’t have much confidence in himself. He works at a deli counter and sleeps gratis on the couch in an apartment rented by two friends, Mark (Jason Schwartzman), who plays a hip high school teacher on a TV sitcom, and Leo (Jonah Hill), another aspiring stand-up comic.

The set-up is familiar, and we can see immediately where it will lead: George will help Ira become his own man while Ira puts George in touch with his own humanity. But Apatow doesn’t have the skill to keep the material from becoming maudlin or the discipline to structure it efficiently. As a maker of sweet, ribald comedies, he relies on a talent for riffing and a willingness to raise the stakes on frat-house humor. But his taste in performers is erratic, and he doesn’t care about plot logic. Knocked Up got away with Rogen’s blunt, unvaried presence and with the improbable premise that beautiful Katherine Heigl would decide to raise a child with an unemployed stoner.

In a drama like Funny People, the limits of Apatow’s skills become glaring. Since Ira’s jokes bomb at The Improv (partly because of his terror when he learns he has to follow George’s set), George’s decision to hire him as a writer is baffling. (George wants to hire Leo, too, but Ira never bothers to tell him about the offer—a glimpse into Ira’s unattractive ambitious side that the movie never bothers to explore.) And if Rogen was uninteresting in Knocked Up, he’s a hole in the screen in Funny People. He doesn’t have an actor’s instincts, so he pummels every line, like a volleyball player who hits every shot with his noggin.

Apatow’s comedies were overlong, and Funny People weighs in at a self-indulgent two hours and 25 minutes. The scenes meander, and the tone shifts back and forth randomly between serious and comic. Especially in the sequence where George and Ira pay a visit to George’s old girl friend, Laura (Leslie Mann), now married to a philandering Australian hunk (Eric Bana, a tense, hothouse actor working painfully hard to get onto Apatow’s loose, improvisational wavelength), there are interludes of up to five minutes in which you have no idea what you’re supposed to be listening to. And the scenes in which Ira squabbles with his roommates or courts Daisy (Aubrey Plaza), yet another would-be comedian, are possibly even worse. The actors seem to be in competition to produce the flattest affect. (Plaza beats Hill by a length.)

The only redeeming feature in the film is also its biggest surprise: Sandler’s performance. His previous attempts at dramatic acting (in Punch-Drunk Love and Reign Over Me) fizzled, but as Simmons he somehow manages to locate the melancholy desperation of a man who realizes he’s thrown away his life.

The funniest bit in the picture is a throwaway: Laura engages George and Ira in her daughters’ favorite game—slathering peanut butter on their faces and lying on the kitchen floor while one of the family dogs licks it off. In another scene, Laura shows a video of her older daughter singing “Memory” in her school production of Cats. When George gets bored, Laura censures him for his inability to be moved by her child’s performance, and the movie clearly agrees with this judgment. The truth is, though, that the little girl (played by Apatow’s daughter Maude) is milking the awful, phony song; there isn’t an ounce of feeling in it that isn’t pure show biz. That Apatow can’t tell the difference is at the core of what’s wrong with Funny People.