A black comedy of errors that manages to be decent enough to watch. Although seriously, this is more of a drama than anything else. Warning, spoilers abound.
So what is Birdman about? It's about a washed up Hollywood actor who used to be super-famous for his role in a superhero movie twenty years ago; the titular Birdman in fact. Now he's trying to regain part of his fame or at least prove his existence was more than just about being Birdman, by writing/starring and directing a play on Broadway. Except he's surrounded by selfish fuck-ups and he ends up being stymied on every end until he has a clean psychotic break. For bonus meta points, they got Michael Keaton to star in the leading role (See Batman, the original movies).
The film itself is strange because nothing really happens in the course of the film. Instead it's all about the character interaction and the relationship drama. And strangely enough it works. Mostly because the supporting cast is full of fuckups as I mentioned previously. The daughter is an ex-drug addict who's angry with her father because he never spent enough time with her and because he always tried to make her feel special. OMG, how dare he right? Edward Norton stars as an egomaniacal jackass who's somewhat sociopathic to the point he tries to forcefully have sex with his costar/lover on stage during a love scene (and somehow the daughter digs this character trait of his...). Then there's the main character himself; who's so obsessed with proving himself that he starts to have a psychotic break over it. I mean, it was pretty obvious that he wasn't mentally well due to having an 'inner' voice that constantly berates him when he screws up. Not to mention he hallucinates Birdman; his acting alter-ego, walking around and talking to him.
Overall the film was decent enough to watch. Not sure I'd buy it on bluray though. There are a few funny moments but it's not really a comedy comedy, but it's more that you're laughing at how screwed up some of these people are. It's definitely not action. It's not romance. It's really just drama.
With regards to the ambiguous ending. I know people who think he jumped and people who think he flew or survived. To be honest, I kind of expected him to be hallucinating every time he exhibited signs of his telekinesis; mostly because that's the way these kind of films go. But let's just review the last few moments, Kevin Costner climbs onto the window ledge of his hospital room, while looking at some birds flying (hence the birdman allegory). Then the camera pans to his daughter who comes in, looks for him everywhere in the room and can't find him and goes to the window. She looks at the ground with a look of dread but doesn't seem to see anything there and then looks up and smiles.
Now what do I think about the ending? First of all, Emma Stone's expression when she looks down at the ground is initially one of dread; as if she's dreading to see her father dead on the ground, but then it turns to one of puzzlement. So obviously, she's not seeing what she dreaded to see. She even scans the horizon curiously, which is not something you would do if your father was lying dead on the curb. She then looks up joyfully. So obviously she's seeing something cool.
The obvious conclusion would be to think that the father is dead and some people have suggested Emma's character has experienced her own psychotic break, seeing her father as Birdman flying in the sky. Unfortunately, I don't really buy that because shared hallucinations are very rare, especially without communication. And there's really no evidence Emma's character is that mentally unstable (or more so than most teenage chars).Remember, Emma has no idea her father hallucinates that Birdman talks to him. However, we do know from the film that the director almost never edits the reaction of other people to Keatons character. Even during the scene where Keaton is hallucinating he's flying around, no one is looking up at him and pointing and going omg, there's a flying man. Instead, everyone reacts normally. The one time everyone reacts with an 'omg' expression is when Keaton's character is standing on a ledge (and he's hallucinating he's flying) so we can probably assume Emma's expressions are meant to be a real expression in the film and not a hallucination.
At this point what is she looking at? The thing is that Keaton's character doesn't always appear to be where he is. In the film, he supposedly flies down to the theater entrance when in actuality, he takes a taxi and disembarks in front of the theater. But the film shows him flying down, which is how he sees it. So even though, Keaton is not shown at the window edge at the end, that doesn't mean he's not necessarily there or somewhere near there. So again, there's a very high chance that he's alive, just not shown in that scene. That's my interpretation anyway.