How much credit does a piece of trash deserve for not only admitting that it’s trash but positively reveling in the fact? That’s the question posed by “Deadpool,” the newest entry from the Marvel Comics stable, which opens with snarky credits that omit names but, among other things, identify the lead as “a really hot guy” but the director as “an overpaid tool” and the writers as “the real geniuses,” while promising “a moody teen” and “a gratuitous cameo” (by Stan Lee, of course). It’s a clever bit, as one would expect from the guys who penned “Zombieland,” but one that proclaim so loudly how different it intends to be from the usual run of superhero movies that you begin to wonder whether the makers are protesting too much.

And indeed they are, because the picture is basically a standard origins introduction to what, presumably, will be a lucrative franchise. What distinguishes it from most other Marvel adaptations—all the “Avengers”-related movies, for example—is its attitude, which might be described as Tony Stark run amuck, with a wildly raunchy streak. (The level of violence is heightened too, but not at similarly exponential levels.) The only previous Marvel effort that staked out a “different” label was “Guardians of the Galaxy,” but it moved in the direction of sheer goofiness rather than this picture’s edgy, even nasty vibe.

That derives from the title character, who—as in the comic—is more anti-hero than hero. He’s Wade Wilson (Ryan Reynolds), who’s introduced behind those credits in his costumed form as an endlessly wisecracking red-garbed masked guy whose skill in shooting, beating and eviscerating his foes is helped by his ability to quickly regenerate when wounded. He’s also apt to interrupt the action by addressing the audience directly, breaking down the fourth wall to brag about his own prowess and insult those around him non-stop.

After the opening confrontation, in which he mows down a passel of bad guys in a caravan of SUVs on a bridge but sees his major quarry Ajax (Ed Skrein), the “British villain” promised in the credits, get away, a battered (and temporarily one-handed) Deadpool goes home, a dumpy place he shares with an equally foul-tempered old blind lady (Leslie Uggams). Her disability is fortunate, in a way, because Wade’s face is hopelessly deformed, looking like a melted plastic mask—which is undoubtedly what it is.

That leads to the inevitable back story. Before the face-melting Wilson is a murderous hit-man who headquarters at a dive where he and his equally brutal associates are assigned jobs by a mysterious outfit and his best buddy is the gonzo bartender, Weasel (T. J. Miller). But he finds true love with a hard-bitten hooker named Vanessa (Morena Baccarin)—the “Hot Chick” from the credits—and the two look like they’ll be permanently together until Wade is diagnosed with inoperable cancer.

That revelation understandably changes things, bringing him a visit by a mysterious man who offers him an experimental treatment at a secret facility run by Ajax. The goal of the outfit, however, is not medical but military—and Ajax puts Wade through a series of excruciatingly painful processes designed to turn him into a mindless killing machine that cannot himself be killed. Of course Wilson escapes and adopts the guise of Deadpool to track Ajax down.

Naturally that won’t be easy, especially after Ajax kidnaps Vanessa. To confront him and his army, whose most powerful member is an Amazon named Angel Dust (Gina Carano), Deadpool will need the help of the two X-Men members, metal Hulk-like Colossus (Stefan Kapicic) and that “moody teen,” grim Negasonic Teenage Warhead (Brianna Hildebrand), who are anxious to see him go straight and join their team.

There are some elements that obviously distinguish this scenario from ordinary superhero fare—the cancer and Vanessa’s occupation among them. But other protagonists in the Marvel canon have personal quirks, too: Stark is snarky, and Peter Parker cracks wise. Wilson simply combines those two qualities and then squares the result, just as at one point he stops to calculate how many walls the script is breaking. He continuously remarks about the clichés of the genre he’s mocking, especially savoring insults hurled in the way of various X-Men characters, including his “buddy” Wolverine. (Of course there’s also a gag at the expense of Reynolds’ “Green Lantern” fiasco.) He’s also quick with sexual barbs and observations that are calculated to shock. The result is a picture that’s an exercise in following established formula while pretending to subvert it by slyly pointing out its absurdities and adding all sorts of nasty pop culture references and profane asides to the mix.

Ryan, with his smirking, boyish quality, is a natural for Wade/Deadpool, and his verbal dexterity is undeniable. Whether you’ll sympathize with the character, however, will depend on your tolerance of his extreme vigilantism and his “everybody-else-be-damned” attitude. Nobody else in the cast excels. Skrein is as much a standard-issue villain as he was a standard-issue hero in the “Transporter” reboot, while Baccarin is attractive but ultimately just the conventional damsel-in-distress. Uggams provides a few laughs, but it’s Miller, with his slacker-esque observations, that scores most often. The technical side of things is okay, as long as you assume that the cartoonish look of Colossus is an intentional joke, and the action scenes are expertly choreographed, though they aren’t what one would call innovative.

The result is a picture that’s the cinematic equivalent of listening to a couple hours of shock-jock radio. Hard-core fan-boys will eat up “Deadpool,” but others may well find its mixture of snarkiness, vulgarity and mayhem indigestible.

And whatever you do, don’t bring the kids.