How strange to think we live in a world where “ordinary person without super powers becomes a superhero” is so common as a plot device that it now has a “formula.” But that’s what “Super” is — formulaic. Though it does shake things up with a couple of surprises, it’s essentially the same movie that anyone would have made if you gave him this premise, and all too reminiscent of “Kick-Ass,” the Batman films, and others of their ilk.

It was written and directed by James Gunn, whose “Slither” was a terrific deconstruction of monster movies and probably closer in spirit to what “Super” wanted to be. Gunn introduces us, with caustic disregard, to Frank D’Arbo (Rainn Wilson), a pitiful man whose two greatest moments in life have been getting married to the lovely Sarah (Liv Tyler) and pointing a cop in the right direction after an escaping criminal ran past him. Much like Rainn Wilson’s character on “The Office” — too much like him, in fact — Frank is a humorless proponent of law and order who sees the world in black-and-white.

Early in the film, Sarah runs off with a drug dealer named Jacques (played by a impressively skeevy Kevin Bacon), leaving Frank devastated and, possibly, delusional. He has religious visions involving a Christian superhero he’s seen on TV, the Holy Avenger (Nathan Fillion), and comes away with this message: “Some of His children are chosen.” Frank comes to understand that he is among these chosen, and that it is his calling to eradicate evil himself.

Now, this is an interesting idea! We’ve seen self-styled superheroes motivated by everything from avenging a murder to impressing a girl, but have we seen one who puts on spandex and fights crime because he believes God wants him to? For a while, Gunn seems to be commenting on religious faith, with Frank going overboard in his zealous efforts to punish the wicked. But this idea, if it’s what Gunn ever intended anyway, doesn’t go anywhere. Instead, he lapses into formula: Frank has a disastrous first outing as the Crimson Bolt; he turns to comic books for inspiration; the girl at the comic shop, Libby (Ellen Page), insists on becoming his sidekick; police are at first annoyed by his actions, later grateful; there is a showdown with an archenemy and his henchmen.

The film does have a few dark laughs, notably from Ellen Page’s very energetic performance as Libby. Gunn succeeds at shocking us a couple times, too, by refusing to shy away from the bloody results of crime-fighting that most superhero stories gloss over.

But Gunn’s overall attitude is unclear. Frank is obviously a psychopath; so is Libby. Yet for some reason Libby is considered a loose-cannon liability while Frank is portrayed as the grown-up — a ludicrous proposition in the face of his insane behavior. (Drug-dealers and pedophiles might deserve a wrench to the skull. Someone who cuts in line at the movies, not so much.) Frank wants to get Sarah back, but we’re not rooting for him to do so — Sarah is unfaithful and awful. Even if she weren’t, Frank is too off-putting a character for us to sympathize with him. He’s a pitiful nutcase who takes away all the wrong lessons from his adventures.

This isn’t a lighthearted comedy about a goofball who tries to be a hero — and that’s perfectly fine. What’s not so fine is the movie’s dour outlook and unlikable protagonist. If this isn’t satire, what is it? A superhero needs a mission. “Super” needs a point.

C (1 hr., 36 min.; Not Rated, probably R for abundant harsh profanity, a lot of very strong violence, a scene of sexuality.)