OMG. I am still reeling from everything. That ending was absolutely mind blowing and amazing. Even though I actually did predict that Booker was an alternate version of Comstock and that Elizabeth was his daughter earlier in the game., seeing the ending and seeing everything play out was crazy. I had chills the whole time.
Just want to clarify some things.
Was it ever explained how Elizabeth was able to open tears? I'm assuming it had something to do with her severed finger that allowed her to travel between worlds? Is that right?
Also Comstock killed The Luteces. So who are the Luteces that you meet throughout the game? Just the Luteces from other worlds? And why did they try to help Booker get Elizabeth back?
Also after all the different Elizabeth's kills Booker, they all start to disappear except for 1. Shouldn't all of them disappear since if Booker dies then Elizabeth/Anna would never be born in the first place. So why does 1 Elizabeth not die?
All in all a fantastic game. A masterpiece of video game storytelling. I even enjoyed it more than the original Bioshock.
1) Yes, that's the general thinking, because part of her existed in more than one universe.
2) Comstock had Fink sabotage their device to get rid of them because they knew about Elizabeth's true heritage (for the same reason he killed his wife). They didn't die, they ended up being stranded in the "limbo" setting you see with all the lighthouses at the end of the game, able to appear and partially interact with any of the other universes. Why help Booker get her back? Revenge for Comstock's actions, quite simply. Although it has taken 123 attempts so far...
3) The camera goes blank before that happens. Does the last Elizabeth vanish? That's left to your judgement. Given what happens in BaS, maybe not.
I just beat it too and one of the things that didn't make sense to me was... Why did New York burn? What was the point of that?
Comstock was born during the Third Great Awakening, and it was quite evident that he was was influenced by the movements of the period. More importantly, I thought that he was postmillennialist, or at least, believed that the second coming of Christ will occur when the entire world converts to Christianity. The way I see it is that one way for him to achieve that is to "drown in flames the mountains of men". He basically refers to the world below him as Sodom, and believes that most of the people below are, more or less, beyond redemption. He also explains his motives in an early-game Voxophone in which he compares Columbia to Noah's Ark.