One walks in to any movie based on a "Saturday Night Live" skit with basement-level expectations. Still, the new "MacGruber" manages to disappoint. The most interesting thing about the picture is that, with a little tweaking, it might actually have been turned into an enjoyable parody of an '80s-style action flick: Bullets fly, stuff blows up, doorway-size heavies lend menace, and it's all been rendered with a knowing fondness for the form by cinematographer Brandon Trost (who also shot "Crank: High Voltage"). But too early on, comedy begins cropping up, and it's all sub-basement from there on out.

"SNL" enthusiasts will know that the skits this picture seeks to inflate are riffs on the '80s TV show "MacGyver," the hero of which was a gun-shy secret agent capable of combining the unlikeliest oddments — a cufflink, a crayon and a cantaloupe, say — into useful tools in stressful situations. The skits mine laughs from the manic incompetence of their special agent, MacGruber (played both there and here by Will Forte), and from the explosions he inevitably fails to abort. The movie attempts to do the same, but after maybe 20 minutes of Forte's frantic, one-note mugging, it's left with nowhere else to go — and there's still more than an hour of this thing to sit through.

The story has MacGruber — long thought dead — being tracked down to the remote monastery where he's holed up by his former commander, Colonel Faith (Powers Boothe). The colonel has a new assignment: stopping MacGruber's old adversary, Dieter Von Cunthe (Val Kilmer), from wreaking havoc with a nuclear warhead he's stolen. Since Von Cunthe is the man who blew up MacGruber's wife 10 years earlier, the legendary agent agrees to take a shot. To this end, he assembles an A-Team of special-ops brutes (all played by professional wrestlers), who are suddenly disbanded when the van into which he's packed them (what else?) blows up. Desperate for replacements, MacGruber recruits an old colleague, Vicki St. Elmo (Kristen Wiig), and a whippersnapper Army lieutenant called Piper (Ryan Phillippe). Wiig remains a master of the throwaway line-reading, but some of the lines she's handed here might have just as effectively been thrown away before they reached her; and Phillippe, for his part, is employed as a wooden straight man whose only function is to endure (along with us) Forte's endless stretchy-faced verbal conniptions. Bad taste is supposed to be a badge of honor in a movie like this, but really, is there anyone left to offend with it? The non-stop barrage of F-words and whatnot unleashed in this film lost any ability to shock long ago; and while the name Cunthe was no doubt good for a giggle around the writer's table, in its 50th repetition here it tests the limits of tedium. There's also more poop humor than one might have thought strictly necessary. In fact, the movie has something of an anal fixation: One of MacGruber's diversionary tactics is to stick a stalk of celery between his thighs so that it protrudes between his bare buttocks; and he's curiously prone to offer up his nether region for rough use by men from whom he seeks favors.

The picture also suffers from a lack of comic precision. At one point, we see Von Cunthe painting a picture using a topless fat old woman as a model. This has the shape of a gag — but what is it? Von Cunthe's art hobby comes out of nowhere and immediately returns there, and we're left with nothing in the way of amusement beyond an old woman's humiliation. Presumably, this seemed funny during the scripting sessions, too.

"MacGruber" demonstrates once again the inadvisability of attempting to stretch a one-minute TV sketch into a 90-minute movie — especially when the lead character is nothing more than an assemblage of over-amped and decreasingly funny wisecracks. "SNL" has been pounding the MacGruber character for more than three years now; could anyone really have thought there was a drop of humor left to be wrung from it? Or an audience parched enough for laughs to want more?

Don't miss Kurt Loder's review of "Solitary Man," also new in theaters this week.

Check out everything we've got on "MacGruber."

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