Step Brothers at its best is a smarter Dumb and Dumber. Out of two wacky main characters and a few slightly less addled supporting ones, it conjures laughs by the dozens. The problem is, they come in clumps.
Will Ferrell and some of his favorite collaborators (including director Adam McKay, who did Anchorman and Talladega Nights) indulge their improvisational talents at their peril. They might as well be putting the film together with a stopwatch - 15 minutes for spastic fights, 20 for inventive profane insults, another 10 for out-of-left-field coups, including an operatic climax almost as uproarious and sublime as the ratatouille in Ratatouille.
Even the best scenes resemble prolonged sketches, and the material meant to bridge them feels halfhearted. Ferrell can be equally great as a put-on artist daring the audience to see through an outlandish caricature, such as his Hitler-loving playwright in The Producers (the funniest thing in that movie), and a comic actor creating an accessible and multilayered character, such as the tenderhearted IRS man in Stranger than Fiction.
In Step Brothers, he plays a 40-year-old man acting like a 12-year-old, and the put-on artist reigns supreme. The movie would be stronger if its mock reality went a lot broader and deeper than the family house that Ferrell and company use as one big rumpus room.
Starring Ferrell as Brennan Huff, who lives with his mother, Nancy (Mary Steenburgen), and John C. Reilly as Dale Doback, an equally arrested lout who lives with his doctor-father, Robert (Richard Jenkins), this movie is slacker farce done as performance art. Roughly 27 years after they left middle school, neither Huff nor Doback has progressed beyond pubescence in social skills and sexual daydreams. (In his treehouse, Dale hoards girlie magazines from the '70s, '80s and '90s.)
When Nancy and Dr. Robert marry, Brennan and Dale descend into infantile panic: They resist turning the Huffs and Dobacks into a blended family. They go through a ticklish parody of the three stages of buddies in buddy movies: suspicion, hate and aggression. It culminates in a no-holds-barred, no-weapons-banned fight that clears the air and cements their friendship. They band together to defeat the wishes of Brennan's unctuous older brother Derek (Adam Scott) to sell Robert's house at 30 percent above market price so Robert can retire and take Nancy on an open-ended cruise.
