Writing reviews becomes its own adventure when battling a dark voice emanating from the corner of the room – specifically an old photograph of myself, questioning all my past decisions in a gravelly Christian Bale voice. That’s the internal battle in Birdman for Riggan Thomson, a former Hollywood A-lister played by former Hollywood A-lister Michael Keaton. The character is rekindling his fame in a Broadway play, having gambled his career and finances on this production of Raymond Carver’s What We Talk About When We Talk About Love – the rickety production is Riggan’s final chance for a positive review before his 90s superhero franchise fame vanishes from memory. Again: that’s Riggan, not Keaton.Alejandro González Iñárritu escapes from his traditional misery fests with a lightly humorous touch in which all suffering is beholden upon touchy actors whose fates are in as little peril as characters from a Preston Sturges comedy. In fact, the production of the play is a 1940s screwball disaster: Lesley (Naomi Watts) is a jittery first-timer; Mike (Ed Norton) is a temperamental bully brought in as a last-minute replacement. The vibe hanging around the stage is so negative, they may as well be putting on Macbeth for all the ill luck hampering each performance.But the willingness for pratfalls and Hollywood satire doesn’t mean Birdman is particularly funny or with any biting criticism. The jokes are directed at easy targets: big Broadway names possess egos, theatre reviewers are snobby, and superhero films make more money than they deserve. Some of the supporting characters (especially Emma Stone as Riggan’s daughter) are sketchy cameos unable to provide the emotional depth required in the final act. There’s little driving urgency or reason to care if the play succeeds or fails, other than the latter promises some bemused reactions by Zach Galifianakis, appearing as a lawyer who picked the wrong assignment.The film’s saving and often quite spectacular grace is its tumultuous rehearsals, strung along under the impression it was all shot in a single take. Aided by cinematographer Emmanuel Lubezki – responsible for the long takes in Gravity and Children of Men – the entire two hours unfurls alongside jazz percussion, walking on a tightrope as if the pretence could collapse at any moment: the kind of audience anxiety one feels at the theatre when the actors have visibly sweaty foreheads. Even if there’s little to be emotionally invested in, each scene is a technical wonder that adds a layer of tension.Iñárritu’s most recent output (Babel, Biutiful) found false mysticism in spiritual connections behind strangers. The difference with Birdman is that the cosmic powers exist entirely inside Riggan’s head. The fiery comets, the loquacious movie poster, and the supernatural powers are one man’s delusion. What we talk about when we talk about Birdman is whether that delusion has any staying power beyond a two-hour rollercoaster ride.