Backstage comedies usually can’t help but be cynical. It’s a perfect place for writers and directors to vent contempt for critics, audiences, actors, incompetent crew and the jerks who put up the money. Hardly anyone minds, either, because we like the glimpse behind the scenes. IF the movie’s good, at least—and Birdman is a great bad time. It’s bitter and raunchy with a sad heart that beats beneath. The solo jazz drums of Antonio Sanchez dominate the music score and provide a perfect backbeat for the film’s curious rhythmic clashes of humor and bleakness. It’s a film full of characters who invade each others’ space and rarely have anything nice to say when they’re there, though it’s often funny in snappy, screwball style. Even when Michael Keaton, great here as a faded star who looks to revive his career with a self-produced Broadway adaptation of Raymond Carver’s minimalist “What We Talk About When We Talk About Love”, is alone, he’s got a prodding voice in his head that encourages him to believe that he has telekinetic powers. It’s a showcase part for Keaton, in the running for the best performance of his career. The rest of the cast rise to the occasion, diving into delicious dialogue and enjoying being a bunch of jerks.