There's more than one way to make a parody. "Walk Hard: The Dewey Cox Story" likes them all. The comedy, starring John C. Reilly as a Johnny Cash/Ray Charles/coal-miner's-daughter-style pop star, contains elements of a Will Ferrell movie (Reilly even runs around in his underwear). It also at times gets close to the understated subtlety of a Christopher Guest comedy. But the movie is best described as the "Scary Movie" of musical biopics, making fun not only of a profession, a la "Anchorman," but also of a type of movie that has become increasingly popular and predictable since Jamie Foxx donned a pair of dark shades and won an Oscar for it.

Hence we get every moment you should now be familiar with, from that hint of the star's present ("You're going to have to give Dewey Cox a minute," his band mate, Tim Meadows, tells a stage manager, "he's got to think about his whole life") that leads to the entire back story (Dewey's brother tells him he has to be "twice as good" after Dewey accidentally slices him in half with a machete) and as many clichéd moments as writers Judd Apatow and director Jake Kasdan could think of along the way.

All the episodes you'd expect in the raucous life of a rock star are represented. Dewey's first wife, loaded with kids, begs him to give up his silly dreams, even after they've moved into a mansion with gold records on the wall. He tentatively tries his first reefer after Meadows warns him, "You don't want none of this mess!" and then admits it's not addictive, hangover-inducing or even expensive. Harder drugs lead Dewey to rehab, medical care being constant attention to how many blankets he has. There are too many times to count when a tragedy leads him to rip a sink off the wall.

The results are sometimes hilarious, sometimes broad, sometimes just weird, and sometimes, like the machete incident, all of the above. Kasdan and Apatow, now a big producer after the success of "Knocked Up" and "Superbad," aren't interested in self-editing. This might be a good thing in terms of hitting as many funny bones as possible with one picture, but from the viewer's perspective, lack of editing can make an uneven film, with as many moments of uncomfortable seat-shifting as there are of laughs.

That said, "Walk Hard" is a little zippier than most comedies. It forgoes the standard plot-filler routine of giving its leads some kind of challenge to overcome late in the movie. Instead, it moves its narrative along, more often than not, through montages backed by whatever current tongue-in-cheek song Dewey has recently concocted.

Most of these songs, like "I Want to Duet With You," are not for the entire family, and neither is the movie. It might even nauseate some of the 13- to 18-year-olds in the target audience. When Apatow and Kasdan decided to forgo reservations, they meant it. You may not want genitals in your face any more than another joke about a chimp or how dopey the Beatles could be, but you're going to get them anyway. "Walk Hard" isn't about protecting feelings, it's about being as crazily comedic as possible, and if that means offending as many people as it tickles, so be it. (R) 96 min. S

Click here for more Arts & Culture