Only on the surface do Phil Lord and Chris Miller — co-directors of the PG-animation Cloudy with a Chance of Meatballs — seem ill matched to the frantic, foulmouthed R-rated comedy of 21 Jump Street.

This big-screen update of the late-’80s TV drama — about twentysomething cops undercover as high school students — is shepherded by Jonah Hill (who stars, executive produces and shares a story credit). The film is not at all interested in the series’ brooding melodrama, so why not hire a directorial duo poised to pull off live-action Looney Tunes elasticity? Quite a bit of Jump is brazen, brash and blustery. Too bad it’s not more of a blast to watch.

Michael Bacall’s script too often restricts the anarchic energy Lord and Miller seem anxious to unleash. In its place are the same boring bits from the very sorts of movies Jump seeks to satirize. Not even this cacophonous comedy can shred the slavish laws of love interests and misunderstandings between pals. Honestly, Cloudy tweaked genre conventions with greater wit, verve and punch. Perhaps Lord and Miller, who wrote that film, should’ve gotten a crack at penning this one. 

After a promising start, Jump wastes many profane breaths trying to be persuasively zany. But only a freeway chase involving strangely non-combustible combustibles and a climactic three-limo shootout hit crazy-good heights of poking fun at overblown cop movies. Cut from the same cloth, both Hot Fuzz and The Other Guys fared better.

It should also more regularly blast its secret weapon named Channing Tatum.

Yes, that Channing Tatum.

Tatum was a daft, daffy slab of beef in 2011’s The Dilemma. However, nothing he’s done suggests much skill at slapstick, deadpan, double takes or zingers. (Unfairly, some say nothing Tatum has done suggests much skill period.) Here, he’s a reliable riot in every scene, often outshining Hill’s growing-stale brand of frenzied shouting. With at least five gutbusters to call his own in Jump, Tatum gives a breakout performance even if the film never quite breaks out.

In a brief prologue, bleached-blond, brace-faced Schmidt (Hill) barely works up the nerve to ask his high school’s resident hot girl to prom, only to be shot down by her and mocked by Jenko (Tatum) — a longhaired jock who will just barely graduate.

Seven years later, Jenko and Schmidt reunite at a police academy. Schmidt struggles with the physical fitness. Jenko struggles with the mental aptitude. Free of high school’s petty hierarchy, each gives the other a hand to graduate.

But bike patrol at a lakeside park is not the law-enforcement badassery they envisioned. There’s no way a flashing set of cherries on a Schwinn is ever intimidating. Almost in spite of themselves, Jenko and Schmidt make a major drug bust that seems a ticket to bigger, badder beats. But Jenko’s inability to properly read Miranda rights gets the case tossed out.

They’re unceremoniously transferred to the titular division — newly resurrected after a long hiatus — and tasked to track drug dealers. As their hotheaded captain, Ice Cube introduces the case with the film’s funniest moment of sick-burn satire.

The drug is called HFS — short for Holy Fucking Shit, as in users’ response to the high — and it’s running rampant in high schools. As often shouted by Cube, the mission is simple: Infiltrate the dealers and identify the supplier.

Seems easy enough until dim Jenko confuses their false identities, casting himself as a straight-A student and Schmidt as the effortlessly cool athlete and drama star.

Soon, these cops — and the movie — begin wasting too much time on their social lives. Schmidt woos a free-spirit senior (Brie Larson) and wins cool points with head dealer Eric (Dave Franco, James’ brother). Meanwhile, Jenko learns to get along with his gaggle of geek friends.

Jump isn’t without fun, winking touches. Connoisseurs of 1990s action will recognize lovingly repurposed strains of The Rock in Mark Mothersbaugh’s score, which is in on the joke. Nick Offerman (of Parks and Recreation) fires off a nice quip about how the 21 Jump Street division is just “recycling shit from the past.”

But its shortcomings are summed up in a scene when Eric enlists Jenko and Schmidt to be his gun-toting personal security. Not knowing they’re cops, Eric lets them try a little target practice because he thinks they’ve never fired a gun. Do you think they try to miss, but inadvertently end up hitting the bottles and cans every time? No. Instead, they immediately tear up the targets like the dead shots they are, and the scene just dies.

Frenetic and loud can be funny on its own. But it requires either the finesse to be smart about playing stupid or sheer, balls-out craziness. Rather disappointingly, 21 Jump Street has a hard time choosing between either destination and takes too long to find its way.