Birdman  is the critically acclaimed dark comedy and drama (directed by Alejandro González Iñárritu) which presents washed-up actor Riggan (Michael Keaton) in and around his new debuted Broadway play.
Quality casting. Time and time again, usually big names attached to movies tend to hinder a film's credibility, merit and sometimes end in disaster (ala Movie 43). Then there are movies that are the exception, the cinematically exceptional Birdman. Michael Keaton, largely known for his widely released Batman  plays Riggans. Edward Norton plays Mike, an intense stage actor. The rest of the cast are Emma Stone, Amy Ryan, Naomi Watts, Keaton and Norton are the top of the crop — Norton for comedic relief and Keaton for his poignant performance.
The ideal marriage of style and substance. Birdman is a technically challenging film — unsurprising because the cinematography was done by the legendary Emmanuel Lubezki (The Tree of Life). According to Lubezki, Birdman is "edited with long takes. the longest take in Birdman actually lasts about 15 minutes, and most are in the 10-minute range." (THR) Then there's the VFX. Birdman showcases a departure from Iñárritu's first film Amores perros, which was more rooted in realism. In Birdman, surrealism is noticebly present.
Sounds just right. This is one hell of a score. Comprises mainly of drums, with several pieces of superbly selected classical music composed by Antonio Sánchez and Victor Hernandez Stumpfhauser. There's Riggan's inner monologue narration as the husky-voiced superhero Birdman.
The dialogue matters too. Birdman is a dark comedy, and it is hilarious, but that will depend on how funny some of the themes are to you personally. Comedy aside, the dramatic notes hit. It's a bittersweet film and a sentimental one. Through Birdman, Iñárritu attempts to expose to us a human experience, something universal: striving to receive validation and meaning. To be seen by the world, the way we want to be seen.
Birdman is an immersive ride into the mind of a man yearning to be more.
Birdman (The Unexpected Virtue of Ignorance)