The one thing Step Brothers does not want for is a good solid high concept: 39-year-old Brennan Huff (Will Ferrell) and 40-year-old Dale Doback (John C. Reilly), two men with crippling cases of arrested development, are forced to live together when their parents marry; the two man-children have to do a whole lot of growing up to survive with each other and help their parents forge a new home together.

The flipside is that Step Brothers suffers as much as any film in recent memory of possessing one and only one gag that it pounds over and over again for its whole running time: watching middle-aged men acting like 12-year-olds with exceedingly dirty vocabularies. Now, I'm not nearly so naïve as to think that there isn't a whole subculture of fans who think that the sight of Ferrell and Reilly running around like big preteens, saying "fuck" in practically every combination imaginable and speaking in vaguely lisping voices is pure comedy gold. I am glad of it; only a sociopath wants for people to see movies and find them hateful, and I expect that the people who pay money to see Step Brothers are by and large the exact same people who are going to get a really big kick of of Step Brothers.

For the rest of us, the film leaves precious little to latch onto, and I'm not afraid to say that it's easily the least-enjoyable of all the Ferrell vehicles I've ever sat through (for context: I liked Old School, I kind of liked >Anchorman and Blades of Glory, and I have no use for the rest). There's this much, at least: Ferrell and Reilly are friends in life, and it's quite obvious that they're enjoying the hell out of screaming insults at each other. Knowing that actors are having a good time counts for something, at least, and in this respect, Step Brothers is surely an affable time-waster. Yet "affable" only takes you so far; and 98 minutes is much farther than that. The film has mutated from good-natured to tiresome long before it hits the end credits.

Easily the strangest thing about all of this, though, is that there's an entire second personality to the film, much less important it must be said, and this Other Film is kind of great. If the A-story is about how two extravagantly immature people become just the slightest bit less immature, the B-story is about their parents, who certainly must have some opinion about their boys' vulgar flailing. These hopeless souls are Brennan's mom Nancy (Mary Steenburgen) and Dale's dad Robert (Richard Jenkins), one a simply terrific character actor and one...well, I know I have affection for Steenburgen, so she's bound to have been really good in something I can't quite call to mind. Anyway, for those of us who like our comedy smart and probing, they get all of the best moments, including their whirlwind courtship at the beginning that is, by my lights, absolutely the comic highlight of the film. It's fairly easy to explain why this should be the case: while the stars are playing what amount to grotesques, Steenburgen and Jenkins play their characters as real human beings, responding to the absurdities of the plot the way that real human beings might, in that same situation. It gives the audience something to identify with and latch onto, and in addition it allows for a level of subtlety that comes as a surprising relief from Ferrell and Reilly's antics. In essence: when Brennan says "fuck" for the 30th time, it's only funny if you think saying "fuck" is funny, but when Nancy says "fuck", it's shocking, believably out of character, and absolutely hilarious. To be frank, I'd have watched a movie that headlined Nancy and Robert falling in love and having to deal with their unbearable kids. I'd have watched that movie ten times over. Steenburgen and Jenkins are fantastic together, and if anything they highlight the flaws in the rest of the project.

Directing all of this is Adam McKay, in his third feature film and his third Will Ferrell vehicle, after Anchorman and Talladega Nights. Bless him for being there, but I'm not at all convinced that he has much in the way of an overriding comic personality (though he did co-write the script with Ferrell, from a story they both co-conceived with Reilly). Sure, he keeps the pace brisk, and he keeps things visually and narratively uncluttered enough that the actors never have to fight for attention, but I find his timing to be just not quite 100% there. Think of a truly gifted comedy director; I have in mind Billy Wilder. Think of how even in his rat-a-tat screwball, he always lets the right moments linger just enough for the characters to twitch a little tiny bit. McKay has no interest in lingering. He plows through the material like he just can't wait to get it over with, for which I suppose I am grateful.

Though in honesty, the Wilder comparison is inapt; that filmmaker always wanted us to know that it was okay to laugh at the characters, and I honestly do not think that's what we're supposed to get from Step Brothers; despite the seemingly evident fact that these are unsympathetic jerks we have for protagonists, I never once got the slightest feeling that we're not expected to find them to be completely lovable, playful guys (in this respect, that the film presents vaguely assholish men as teddy bears, it is comfortably within producer Judd Apatow's métier). For my tastes, this is a tremendous error; but this is not a film made for my tastes. I expect that by now, this is probably an obvious fact.