I personally don't look it as a dream. Because all the events in the game did happen (and in fact multiple times), it's not like you did all the things in the game for nothing. The difference is that Comstock, Columbia and adult Elizabeth will no longer exist in any other dimension, which in itself is very sad.

1)That doesn't mean that the booker's that kept anna would be happy either, unless for some arbitrary reason none of the alternate universes had booker or anna being unhappy. In Universes A) Some booker and elizabeth's would be happy some wouldn't, B) Wouldn't some elizabeths and booker inevitably end up with an unhappy life too? 

2) My issue is, Elizabeth's relationship was the best thing about the game for me. The quantum/time travel was well fairly well done, but not more so than a movie I would give 3.5 stars (Looper). It's obviously a preference. There was nothing wrong terribly wrong with the ending from a mechanical standpoint, and is really quite good for a videogame. Just imo, it abandoned the games strengths for an ending I've seen before though not frequently, that's my criticism.

To say I want a hollywood ending is idiotic, and non hollywood endings are really quite available to see.
Looper has an ending that's extremely similar to this, but was more emotionally satisfying and still had issues. 12 monkeys has an ending that's similar to this. Lust, Caution, Oldboy, Infernal Affairs, Pan's Labyrinth, Ghost In The shell, blade runner different story's with not typical endings that are my favorite movies. Stein's gate is visual novel game like thing, which has like 9 endings caused by various consequences of time traveling, specifying the rules a little more clearly.

1) That's the thing about the multi universe thing, if a person is happy in one it doesn't mean the other is. There's probably millions of Bookers who are unhappy with Anna, but that's something we have to realize that will never change. But the point of the game is to stop the tortures and the kidnapping Comstock did to Elizabeth, that was the ultimate goal of the game. The other things are just questions that don't really have an answer. 

2) I agree that the relation between Booker and Elizabeth is amazing, and it's sad to know that the relation will never happen in the future, but that's the best for the characters. The relation was great yes, but at the expense of a crazy man who kept her daughter locked and torture her, not "knowing" each other like that is probably a happier solution.

Never watch Looper but I agree with some of the examples you mentioned (especially Pan's Labyrinth), one game that also has a mindfucked ending is 999 for the DS (9 hours 9 persons 9 doors) it's also a visual novel, I recommend it if you haven't played it.

Just so anyone knows because it appears I'm being extremely negative. I'd give this game a 9/10 because it is very great and one of my favorite games this gen. I'm currently playing it again in 1999 mode. What I've said, combined with some gameplay issues keeps it from being more than that for me atleast.

I can name a lot of things in my favorite games, that I wish would have been different. I just am very critical of everything for whatever reason :P.

I've just finished the game yesterday and I have one question:

Why is there one Elizabeth remaining at the end? Booker had his daughter in the "no baptism" timeline so if he dies at the baptism then there should be no Anna/Elizabeth... right?

Most flawed ending in a game I've ever seen. Although nobody understands it they call it a masterpiece. The complexity of the story is compensated with an infinite amount of plotholes.

She may disappear at the end though. Like Inception because the noise still occurs indicating she disappears. But I guess after all that hard work they didn't want to confirm it was all for nothing.

Similarly, after the credits there was another scene with Booker and Anna, back in his office but with no Lutece there to take her. Perhaps this is the "victory" ending that Elizabeth was trying to acheive? I imagine we will get more in the DLC about that, though.

Such as?

I shouldn't have skipped the credits then!

As a big fan of TV show Fringe, I pretty much predicted most of the ending to Bioshock Infinite about half way through the game, especially how Comstock bought the child from a younger version of himself and that you in fact play a version of himself.

However, it was still an incredibly gripping last 30 mins and all the pieces of the puzzle fell very well together regardless of how much of the story I figured out before hand.

Alas, because I know how it would go down, the twist in the original Bioshock shocked me more. Excellent endings for both games.