When you build you career on a foundation of misery, at some point you have to shake things up. It feels like Alejandro González Iñárritu has arrived at that stage. His first three films—Amores Perros, 21 Grams, and Babel—established the now oft-imitated plot structure of disparate people ruining each other's lives, both intentionally and unintentionally. With Biutiful, he delved even further into the depths of despair for a grueling two and a half hours. As Michael Phillips said on Filmspotting, "I think Biutiful is still going, and we all just decided to stop watching."

Something happened to Iñárritu, and now he has a sense of humor. His latest film, Birdman, or the Unexpected Virtue of Ignorance, is no less showy or ambitious than the previous films, but it has its mind set on a (slightly) brighter side of life. Michael Keaton stars as Riggan Thompson, a washed-up movie star who was once famous for playing a superhero in a massively successful film series, an opportunity that he threw away for the sake of artistic integrity. The meta nature of his character is not lost on Iñárritu, and is only one aspect of the film that is self-reflexive. He has decided to jumpstart his career by directing, adapting, and starring in a production of Raymond Chandler's What We Talk about When We Talk about Love. The story has a lot more going on, but that's the gist of it.

What I want to talk about is the filmmaking. The gimmick, which has been explored in other equally ambitious films, is that Iñárritu wants to convey the impression that we are witnessing the action all in a single take. He employs Emmanuel Lubezki (Gravity) as the cinematographer, and uses a constantly moving camera that tracks the actors around the set in extremely long, intricate takes. Iñárritu and his editor have some tricks up their sleeves to throw in an invisible cut here and there, but overall, the illusion works. This challenging gambit would be only a gimmick if it didn't also serve the purpose of ratcheting up the tension, which is already at a fever pitch because of the play's disastrous progress.

The film's jazzy, percussive score by Antonio Sanchez further increases the tension, in addition to spicing up the transitions between scenes. Since the film is meant to feel like it's all in one take, we spend a lot of time following characters as they walk between rooms in the cavernous St. James theater. While this occurs visually, Sanchez's contrapuntal drums convey a sense of unease. They lack structure and definite rhythm, and sound like random crashes and explosions inside the characters' brains. At one point, Riggan walks past the break room of the theater, and we see a brief shot of a man playing the drum music, breaking the fourth wall and undermining our confidence in Riggan's psychological state. The film is deeply enhanced by the score, and the score likewise cannot exist outside of the film. Although it is effective within the confines of the film, it likely would not be able to stand on its own. As a result, it feels even more connected to the story.

The main cast is a rogue's gallery of wonderful actors, including Edward Norton, Emma Stone, Amy Ryan, Naomi Watts, Andrea Riseborough, and Zach Galifianakis. Norton, also in a meta role, plays a well-regarded but extremely difficult-to-work-with actor who is brought in at the last minute to replace one of the leads of Riggan's play. Stone is recently out of rehab, Riggan's begrudging assistant, as well as his neglected daughter. Ryan, in a bit of casting that reminded me of her role on The Wire, plays his heroically forgiving ex-wife. Watts plays an insecure actress in the play who is on pins and needles to be playing on Broadway for the first time in her life. Riseborough is an actress and Riggan's girlfriend, who complicates matters a bit when she announces her pregnancy on opening night. Finally, Galifianakis plays completely against type as Riggan's manager, the only sane person in the room who is holding everything together. Their performances are excellent across the board, and they prevent the film's formal ambition from distracting too much from the story.

Perhaps my only complaint about the story is that it presents nothing we have not seen before already. Backstage dramas are common in film, especially ones about the psychological tolls of being a performer (The Red Shoes, All That Jazz, Black Swan). But it's good that Iñárritu plays its safe with the story, because when given free rein, he can have a tendency to stray into maudlin territory and get mired there. The screenplay was co-written by Iñárritu and three other writers, which could explain why it feels so different from his previous work. Birdman is easily Iñárritu's best film yet, and we should be hearing about it lot more come Oscar season.