“Birdman” opens in a dressing room at Broadway’s St. James Theatre, where a fifty-ish man in tighty-whiteys sits meditating. And levitating. And hearing a guttural, self-doubting voice in his head berating him for falling this far. The man is Riggan Thomson, once the star of a blockbuster superhero franchise, now washed-up and trying to revive his career by starring in a stage version of a Raymond Carver story that he adapted and directed himself. Also, either he’s losing his mind, or he really does have superpowers. Or maybe both.

Riggan Thomson is played by Michael Keaton, who of course played a Birdman-like superhero 25 years ago and subsequently fell off the radar. “Birdman” is a showbiz satire, a backstage comedy, and a semi-absurd depiction of actor insecurity, directed and co-written by Alejandro Gonzalez Iñarritu, whose previous films (“Amores Perros,” “Babel,” “21 Grams”) were, uh, a lot more serious than this. Whatever inspired him to get silly, the manic energy and overriding sense of fun in “Birdman” are most welcome.

Things are chaotic on the last day of rehearsal before the play is to have its first public performance. Riggan isn’t sure what he’s doing, female lead Lesley (Naomi Watts) is nervous about making her Broadway debut, supporting actress Laura (Andrea Riseborough) might be pregnant with Riggan’s baby, and the fourth member of the cast is sidelined by an injury (which Riggan may have caused via telekinesis).

His replacement is Mike Shiner (Edward Norton), an acclaimed Method actor and legitimate thespian who comes in already memorized and with notes for Riggan about how to tighten the dialogue. Mike sneers at movie stars like Riggan, at fame in general (“Popularity is the slutty little cousin of prestige”), and at Hollywood phonies who think they can just waltz onto Broadway and be real actors. He, too, might be insane, evidenced by his insistence on drinking real liquor onstage and by his flirtation with Sam (Emma Stone), Riggan’s ex-junkie daughter who’s half-working as his assistant now.

The first chunk of the movie has a zippy “Noises Off” feel to it as the actors work on the play while grappling with their offstage problems. Producer Brandon (Zach Galifianakis) runs around handling producer things; Riggan’s ex-wife (Amy Ryan) stops by; there’s an encounter with a vindictive theater critic (Lindsay Duncan) at the bar next door. Through it all, Riggan often hears his own Birdman voice in his head, berating him and second-guessing his decisions just as Mike Shiner is doing right in front of him. Something’s gotta give, and it might be Riggan Thomson’s sanity.

Now here’s the part I didn’t tell you yet. Through painstaking planning and rehearsal (and aided by digital trickery), the film is made to look like one continuous, unbroken take, with no cuts. The camera starts in Riggan’s dressing room and follows him and the other characters around the theater, through hallways and onto the stage, up to the roof and around the block. Sometimes the camera will go by itself from one scene to the next, and we’ll realize contextually that the next scene is taking place hours later. In that way the film manages to look like it’s a single 119-minute shot even though the story spans three days. The effect is that the movie feels like one continuous performance — like a play, in fact.

It’s amazing to behold, to marvel at the sleight-of-hand, seamless digital effects, and good old-fashioned legwork needed to pull off such a stunt. The performances have to be spot-on (because they can’t be fixed with editing), actors have to hit their marks precisely, camera movement must be meticulously mapped out. Is it a “gimmick”? Yes, in that it’s meant to attract attention (the dictionary definition of the word). An unusual shooting style, especially one that makes shooting harder, does tend to say, “Look at me!” But it’s also a fun challenge for a director, a nifty trick that’ll razzle-dazzle ’em if he pulls it off. It’s showmanship! Ain’t nothing wrong with that.

The trick is only a problem if it’s intended to distract from a movie’s weaknesses — if the movie’s no good without the gimmick. With “Birdman,” the heightened sense of immediacy offered by an unbroken take does give the movie an extra thrill, but it’s a loose, funny script anyway (if slightly disorganized), the sort of story that would be entertaining no matter how it was shot. The lunatic performances by Keaton and Norton are the highlights: unhinged, totally liberated (all the more impressive given how carefully choreographed they had to be), and completely devoted to the multifarious nuttiness of their characters. They’re a lot more interesting to watch than a guy in a cape and tights.

B+ (1 hr., 59 min.; R, abundant profanity, some nonsexual nudity, sexual dialogue, brief violence.)

Originally published at Complex.