Cast members Nick Swardson (2nd L), Jesse Eisenberg (C) and Aziz Ansari (2nd R) pose with models during a photocall to promote their film "30 Minutes or Less" in Cancun July 13, 2011.[Photo/Agencies]

If this has indeed been The Summer of the R-Rated Comedy, with each new movie striving to one-up its predecessors in getting down and dirty, then we're going out with a whimper with "30 Minutes or Less." And that's ironic, given that the movie is all about something - or someone - going out with a bang.

From the phoned-in ("The Hangover Part II") to the fantastic ("Bridesmaids"), "30 Minutes or Less" falls somewhere in the mushy midsection. Like "Horrible Bosses," it's got a shaggy, sloppy vibe and characters who are in way over their heads, but it's not nearly as consistently funny. It's actually got more in common with the "The Change-Up" in that it's frustratingly uneven, despite some appealing moments of buddy camaraderie.

Jesse Eisenberg leads the idiocy - and that's part of the problem. Eisenberg is at his best when he's the smartest guy in the room, when he's struggling to stifle his inability to suffer fools, as in his Oscar-nominated performance in "The Social Network" or even in films that have allowed him to show some more insecurity, like "The Squid and the Whale" or "Zombieland" (which, like "30 Minutes or Less," came from director Ruben Fleischer).

Here, he's one of the fools himself as Nick, a slacker/stoner/pizza delivery guy whose only ambition in life is to get an order to its destination in a half-hour or less, hence the title. Not that punctuality is a source of pride for him; rather, if he doesn't make it in time, the customer gets the pizza for free and the cost comes out of his paycheck. His best friend, Chet (Aziz Ansari), is vaguely more useful in that he's an elementary school teacher, but he's still sort of a goof-off (which calls to mind yet another of the summer's R-rated comedies, "Bad Teacher").

The other pair of pals in "30 Minutes or Less" consists of the flat-out doofuses played by Danny McBride and Nick Swardson. McBride's Dwayne hates his disdainful Marine father (Fred Ward) and dreams of proving himself by opening a tanning salon that's a front for a brothel. With some inspiration from a stripper named Juicy (Bianca Kajlich) and some help from Swardson's worshipful Travis, who's obsessed with explosive devices, Dwayne cooks up a scheme to kill his dad and thereby inherit the old man's millions in lottery winnings.

But first, Dwayne needs $100,000 to pay the hit man (Michael Pena as an amusingly over-the-top ethnic stereotype). So he cooks up another scheme to order a pizza, then kidnap and place a bomb on the poor schmo delivery guy and force him to rob a bank, or else he'll blow the guy up.

None of this crackles with the kind of breezy, madcap hilarity that it should; it's actually rather tortured and convoluted. Merely trying to explain what the plot was about just now was arduous. Similarly, everyone feels as if they're straining here, trapped in their one-note roles, and they probably wouldn't have had to work so hard if there were more to the script from Michael Diliberti.

It almost feels as if "30 Minutes or Less" were constructed from a random assortment of wild and raunchy ideas: words on notecards like "hooker," ''stripper," ''gay slurs" ''flamethrower" ''adultery with a lifeguard" and "fellatio in a car." It feels way longer than its brief running time, not just because of its stop-and-start pacing but also because it looks so drab and dingy, it's really unpleasant to watch.

Even actors as delightfully odd and fearless as McBride and Swardson, who have their moments, can't make this thing explode off the screen.

"30 Minutes or Less," a Columbia Pictures release, is rated R for crude and sexual content, pervasive language, nudity and some violence. Running time: 83 minutes. Two stars out of four.