Birdman is by no means a conventional film. Almost the entirety of the film is presented to us a single uninterrupted take, a development of cinematographer Emmanuel Lubezki's trademark long takes, who also worked on Children of Men and Gravity. Although initially distracting, this technique is surprisingly effective, both grounding the film and helping the story to flow while also adding a sense of surreality that Birdman thrives off. The audience is expected to know when time has passed or a scene has changed with little to no indication from the film itself, and although this can seem strange at first it really shouldn't pose much of a problem for anyone paying attention. It's an example of one of the ways that Birdman credits its audience with intelligence, something that's always refreshing to see, and something to is unfortunately quite rare.
The initial surrealism caused by the one take presentation of Birdman is only added to throughout the films running time in various ways, and is played with to keep the audience guessing about where the film is heading and the intentions of its characters, most of who are fully realised and well developed as the film goes on. Strangely, the meta qualities of an actor who played a superhero in the early 90's playing an actor who played a superhero in the early 90's is never really "used" for anything - Keaton is fantastic in the lead role, giving a potentially career rejuvenating performance, but as far as the film itself is concerned anyone could have played Riggan and nothing would have been lost.
The idea that Birdman offers a satirical look at modern superhero films seem entirely unsubstantiated after watching it. Riggan could have just as easily played a more conventional action hero or the lead role in any financially successful film without changing the way the film deals with him and peoples reaction to him. There is some small commentary on the Hollywood invasion of Broadway, but again this isn't superhero specific and it's by no means the main focus of the film - if Birdman was intended to be a satire, then it went straight over my head. There's a sense of self importance to Birdman that comes off as overly pretentious in the parts when it does try to be satirical - whether that's an intentional reflection of the way Broadway sees Hollywood or Riggan's sense of self importance is debatable, but might be giving the film a bit too much credit.
Instead, Birdman works best as a character study. Riggan is a broken, depressed human being, both damaged as a person and damaging to those close to him, delusional in a multitude of ways and hated by the Broadway community who see him as an imposter and whose approval he so desperately needs. I previously mentioned that Keaton is fantastic in the role, and that's a sentiment worth repeating - Riggan is a well written character anyway, but Keaton embodies him perfectly, not because they both played superheroes in the 90's, but because he gives a really convincing performance that the film pretty much relies on.
In fact, most of the cast give performances that could be described as if not necessarily career defining, then at least a reminder of what they can do. Edward Norton is great as Mike Schilling, the popular yet abrasive method actor who acts as a mirror image of Riggan on a different life path. His character is clearly meant to be a heightened version of Edward Norton, who is well known as being difficult to work with, but it's a great performance nevertheless, adding depth to a character that could have come across as too antagonistic to be likeable. Emma Stone's portrayal of the drug addicted daughter of Riggan is far stronger than the writing that she is working with, and makes what could have been a clichéd character matter to the audience. The same is true of Naomi Watts who plays Lesley, a new to the stage actress and the under-appreciated girlfriend of Mike, who despite limited screen time really manages to make an impression, and it's good to see Zach Galifianakis drop the stupid but sweet persona he is known for and play an actual character.
Birdman isn't quite the biting satire of blockbusters that many were hoping for, but it's still a thoroughly entertaining, ambitious character study with a number of great performances and interesting cinematography, and is a film that will no doubt be discussed for a long time yet thanks to the openly interpretive and surreal nature of large portions of the film. It's dark (but not too dark), smart (albeit not as smart as it thinks it is) and suitably funny when it needs to be, and is a great start to cinema in 2015 if you have anything more than a passing interest in films.