Stone-faced and mullet-topped, Will Forte brings his

Saturday Night Live

action ninny to the big screen in

MacGruber

.

Saying and doing stuff that he'd never get away with on network television (including some business with a celery stalk that I'd rather not get into), Forte is the idiot savant - no, make that just plain idiot - at the center of this affectionate and not altogether slipshod nod to '80s-era Schwarzenegger, Stallone, and Willis vehicles. And, of course, MacGruber owes a bit more than its name to that action spy-guy TV series, MacGyver, too.

More successful at spinning off a sketch comedy character than other SNL screen projects (It's Pat, or Stuart Saves His Family), MacGruber has been fleshed out to feature length by Forte and cowriters John Solomon and Jorma Taccone (Taccone also directs). Val Kilmer, wearing a tight ponytail and a demonic grimace, is the villainous Dieter Von Cunth, but most people just call him by his last name. And that's about the level of sophistication this comedy aspires to.

As the story begins, Cunth and his henchmen have hijacked a nuclear warhead in eastern Siberia. MacGruber, whose bride (Maya Rudolph) was killed as the couple were saying their vows, has retired from his gig as an ace military Special Ops secret-agent dude, and is leading a monastic life in a small town in Ecuador. But he's needed to save the world, of course, and a Pentagon colonel (Powers Boothe) persuades MacGruber to try to do just that.

On MacGruber's team are a young army lieutenant whom MacGruber doesn't like at all - played with admirable straight-man implacability by Ryan Phillippe - and Vicki St. Elmo, a singer and former MacGruber flame. Deadpan comedic actress Kristen Wiig, game and goofy in the role, is particularly winning when she's required to disguise herself as MacGruber, mullet and all - thereby putting her life in jeopardy. A little while later, she dons a fake beard to double as one of Cunth's lieutenants, placing herself in imminent danger yet again.

In fact, MacGruber's survival skills seem to begin and end with persuading other people to put themselves between him and the bad guys.

Operating on a plane of jokery that rarely departs from the bathroom (and when it does, it's to explore a middle schooler's idea of sex jokes), MacGruber is by no means a work of genius, or a piece of art, or even very good.

But Forte and company have managed to make crude and lewd dunderheadedness laugh-out-loud funny here and there, and that, I guess, is something of an achievement.

MacGruber **1/2 (out of four stars)

Directed by Jorma Taccone. With Will Forte, Kristen Wiig, Ryan Phillippe, and Val Kilmer. Distributed by Rogue/Universal.

Running time: 1 hour, 28 mins.

Parent's guide: R (profanity, inanity, violence, sex, nudity, adult themes)

Playing at: area theatersEndText

Contact movie critic Steven Rea at 215-854-5629 or srea@phillynews.com. Read his blog, "On Movies Online," at www.philly.com/philly/blogs/ onmovies.