With Birdman, filmmaker Alejandro González Iñárritu modulates his typically bombastic style into a bold comment on the uncertain new frontier of performing arts. The movie is technically complex yet strangely facile, so maybe that’s the comment right there. Michael Keaton plays the wounded, ambitious, has-been star of a superhero-movie franchise, now mounting his own Raymond Carver adaptation on Broadway. This involves feather-ruffling negotiations with Zach Galifianakis as his producer, Amy Ryan as his ex-wife, Emma Stone as his fresh-from-rehab daughter, and a cast of variously challenging fellow performers including Andrea Riseborough, Naomi Watts, and Edward Norton. Shot by Emmanuel Lubezki, it all looks exactly like an answer to the question of what would be next from the guy who won an Oscar for the cinematography in Gravity. Though shoehorned into three play-like acts, Birdman transpires in one long bravura take — which appears to contain some hidden cuts, à la Hitchcock’s Rope, and some CG tricks of the sort that blow the illusion by reminding us we’re in a realm where anything’s possible so nothing’s truly wonderful. (The single-shot movie to beat still is Russian Ark.) Iñárritu’s try-too-hard mode of magical realism can be breathtaking, absolutely, and it also can backfire. But the film evinces at least partial awareness of this conundrum, preoccupied as it is with dorm-room-argument-style questions of artistic integrity and relevance. It’s all so on-the-nose, including a bit about a nose, and the boldest gestures are predictable and protracted, like Keaton’s character’s rather basic dilemma, into florid tedium. Still, it is a fine showpiece for his range, which too few movies have been.