Meta is at the heart of the film, from the casting of Keaton, to the interplay of the various actors and plot lines, to the realism/naturalism vs. artifice of art that unfolds within the walls of the theatre. It flirts with magic realism through Riggan’s ‘Birdman powers’, which is contrasted with the lifelike movements of the camera that moves through the cramped, gritty artifice of the stage and backstage. As well as the naturalism vs. artificiality of art, another central concern is between the showiness of Hollywood and the ‘integrity’ of Broadway. This adds to the ironic factor, the film presenting itself as a serious, Art-house style film despite its Hollywood origins. Both these strands are linked with the eye of camera, with the bulk of the film being one long, artificially pieced together take with the camera gliding through the constructed world of the stage and the backstage of the theatre, being simultaneously raw and real while entirely artificial. It contrasts the naturalism and integrity of the stage with the artifice and ostentation of Hollywood combined into one.
None of this is subtle, and the self-conscious irony that drenches the film can be fatiguing, and will (and has) put a lot of people off. But if you go past the somewhat haughty conceit of the cast and crew, Birdman provides a playful, involving, engaging, and certainly potent experience.