Look, I laughed about a dozen times during Bad Grandpa. Big, dumb, moronic guffaws. I'm not proud of it, but there it is. And that, in essence, is all there is to say. This movie has nothing else on its mind, and its particular brand of bathroom humor will either hit the sweet spot for you, or it won't.
If you've seen Jackass, then you're probably familiar with Irving Zisman, Johnny Knoxville's dirty-old-man persona who specializes in public displays of hapless embarrassment. Here, they've crafted an entire movie around him, bound by the loosest of all plot threads but basically sticking Knoxville-as-Zisman in a store or street corner and watching the (real-world) public's response. I confess I prefer Jackass's surreal stunts — something about grown men getting trampled by farm animals just speaks to me — but they're trying something a little different here and for the most part, it works.
Knoxville has a fitting partner in crime for his shenanigans: eight-year-old Jackson Nicoll, playing Zisman's sad-sack grandson. When Mom earns herself a spell in the clink, Irving has to take the lad to his redneck father's house. The old man is less than thrilled about it since his wife just died and he's eager to test the waters of senior singledom. But otherwise, there'd be no movie, so off they go with grandma's stiff corpse in the trunk and a whole gaggle of unsuspecting Americans in their way.
Zisman isn't a character so much as a fulcrum for Knoxville's unique brand of comedy. He and Nicoll tinge the story with shades of sadness -- the pathos of the scenario bleeds out of every scene -- but they're basically there to see what kind of a rise they can get out of innocent bystanders. Zisman gets drunk at a bingo game and hangs out at an all-male stripper revue, while the pair shoplift, crash weddings and generally make asses of themselves. Everyone else looks on with a mixture of bemusement and horror.
The trick is that those reactions are genuine. Knoxville, Nicoll and a couple of incidental players are in on the joke. Everyone else is just plain folk, unaware that they're being filmed and justifiably off-put by the antics they witness. Whatever spark of verite is generated by that scenario, Knoxville knows how to summon it. It's funny stuff… or at least funny enough to hold our attention throughout the majority of the running time. Some of it doesn't work and the film has its share of flat moments where the gross-out humor can't find any traction. But the hit-to-miss ratio is appreciably high, and the last few scenes actually manage to find a little heart amid the epic raunchiness,
Bad Grandpa most closely emulates Borat and similar efforts from Sacha Baron Cohen. But it's not nearly as ambitious as those movies, and as such it doesn't segue into active cruelty the way Cohen's efforts do. Director Jeff Tremaine isn't trying to expose his subjects' inherent flaws or prejudices. Indeed, Bad Grandpa seems to celebrate the tacky underbelly of America: neither judging nor shaming the people it depicts but sharing in the thousand petty exasperations of life with them. At the end of the day the only real idiots onscreen are the old man and his grandson gleefully jerking the public chain.
You can see that in the closing credits, which includes shots of the subjects chuckling good-naturedly after being told they're in a movie.
It's not everyone's cup of tea and if you've seen the ads you can probably make that call for yourself. But Bad Grandpa doesn't hide its nature, and those who appreciate Knoxville's particular brand of fun are apt to find a very dirty good time waiting for them here. You either laugh or you don't. The naughty boys (of all ages) onscreen know what they're trying to do, and are perfectly fine with either result.