Seth Rogen and Zac Efron make for amusing alter-egos in “Neighbors,” a shaggy, baggy collegiate comedy that is less a coherent movie than a loosely assembled series of lewd jokes and punishing slapstick routines.

Unfortunately, one of the funniest sequences — involving a prank with purloined air bags — has already been overworked to death in “Neighbors” trailers, which also have tipped the film’s hand as to its edge-dwelling sense of humor. Viewers who find unbridled hilarity in the idea of babies eating condoms, men dueling with sex toys and 30-something yuppies keepin’ it trill by using words like “trill” will find much to value in “Neighbors,” as long as they don’t get lost in such little details as credibility or lost opportunities.

It seems like just last year that Rogen was cinema’s reigning arrested adolescent, cavorting with pals James Franco and Jonah Hill in “This Is the End.” In “Neighbors,” Rogen is (almost) all grown up as Mac Radner, who with wife Kelly (Rose Byrne) is raising the world’s most awesome baby in a cozy college-town bungalow. When the house next door is sold to a fraternity, the Radners at first try to make nice with the group’s president, a bronzed, charming cock of the walk named Teddy (Efron), who immediately invites them in for beer and magic mushrooms.

It’s all rainbows and unicorns, of course, until the frat’s next rager, which leads the Radners to call the police. What ensues is a picket-fence feud of escalating traps and dirty tricks, each more vulgar and explosively violent than the last.

Directed with characteristic haphazard style by Nicholas Stoller (“Forgetting Sarah Marshall,” “Get Him to the Greek,” “The Five-Year Engagement”), “Neighbors” isn’t designed to impress with subtle comedy or clever construction. Rather, it’s a movie of wammies: one-liners, shticks and sight gags that don’t gain in momentum or accrue in meaning. They just happen, quickly, then get out of the way to make room for the next ones.

Although Byrne has some promising moments as a bored stay-at-home mom, and Lisa Kudrow shows up in a weirdly un-funny cameo as an uptight college dean, “Neighbors” is primarily a bromance: between Teddy and his best friend, Pete (Dave Franco), a bespectacled brain whose love for his Adonis-like leader is clearly much deeper than fraternal, and between Mac and Teddy. Rogen and Efron both prove to be excellent sports when “Neighbors” exploits their dramatically different physiques, first during an amusing dance-off and in an improbably rewarding payoff at the end. (As for Mac and Kelly’s preternaturally cute baby, Stella, she is adorably and expressively played by twins Elise and Zoey Vargas.)

Until then, however, viewers must slog through all manner of crude, coarse, often lazily choreographed bits that feel rote and barely warmed-over, from a graphic anatomical stunt performed by the actor Christopher Mintz-Plasse to a dumb scene involving Robert DeNiro impressions. (If the part where Rogen and Efron engage in a “Batman” voice competition seems familiar, it’s because Steven Coogan and Rob Brydon did it first and better with Michael Caine impressions in “The Trip.”) Still, “Neighbors” will no doubt reward audiences who demand little more than a few broad, easy laughs to be entertained, which, after all, describes most filmgoers these days. To quote Mac and Kelly in their best undergraduate patois: I’m not judgin’, I’m just sayin’.

★ ★

R. At area theaters. Contains pervasive profanity, strong crude and sexual content, graphic nudity and drug use throughout.
96 minutes.