Shakespeare’s “Coriolanus” is not staged as often as most of his other plays, and it’s never been adapted into a theatrical film before. The reason for this isn’t that it has the word “anus” in the title (though that might be a factor) but that the main character is a haughty, tantrum-throwing mama’s boy. An audience can sympathize with a protagonist who’s flawed; a protagonist who’s just a snotty bastard is harder to accept.

I don’t know what combination of bravery and foolishness possessed Ralph Fiennes to choose such a problematic play for his directorial debut — and he plays the title role himself, too — but he pulls it off. Aided by John Logan’s screenplay adaptation, which downplays high-born Coriolanus’ contempt for common folk, Fiennes makes the guy seem like a genuine badass, flawed but not completely beyond hope.

This version moves the action from ancient Rome to modern times, in a country rocked by civil unrest, food shortages, and the drumbeats of war. Gen. Caius Martius Coriolanus (Fiennes), a ferocious war hero whose victories have won him the admiration of the lower classes he despises, is drafted for political office by his formidable mother, Volumnia (Vanessa Redgrave), and by Menenius (Brian Cox), a longtime mentor and a political operative. Caius’ wife, the genteel Virgilia (Jessica Chastain), recognizes that she isn’t needed in this equation, and that she especially shouldn’t get between her husband and his mother.

But Caius Martius is too proud and temperamental to put up with the realities of politics. Why should he be forced to show the citizens his scars, figuratively or literally, just to get their votes? His opponents are only too happy to exploit Caius’ hot temper and paint him as a supercilious elitist (which, to be fair, he is). Eventually Caius finds that his best ally might be his lifelong nemesis, Tullus Aufidius (Gerard Butler), who leads the army of the city-state that is forever trying to conquer Rome.

The film is shot in a gritty, verite style that emphasizes the warfare aspect of it; the cinematographer, Barry Ackroyd, worked on the similarly stark-looking “Green Zone,” “The Hurt Locker,” and “United 93.” Meanwhile, the dialogue is pure Shakespeare. This combination of hyper-realistic and modern visuals with poetic Elizabethan language gives the movie a surreal, dreamlike quality that couldn’t have been achieved if Fiennes had kept the ancient setting. Some of the details of the play don’t fit in the modern world, but that wrongness only enhances the film’s eerie quality.

Fiennes, Redgrave, Cox, and most of the rest of the cast are old pros at this sort of thing, navigating the tricky language with confidence and giving meaty, entertaining performances. Butler is noticeably less skilled at it than Fiennes is, which shows especially in the scenes they have together, “beard to beard,” as Tullus puts it. (Butler’s impenetrable Scottish accent doesn’t make the action any easier to follow.) For Shakespeare aficionados, it’s nice to finally have a big-screen version of one of the Bard’s more difficult plays. That it’s a solid, respectable adaptation to boot is icing on the cake.

B (2 hrs., 2 min.; R, some moderately strong violence.)