Your post makes things a lot clearer. Bioshock is hard to understand. But one question. At the end, we saw that there was only one Elizabeth when booker died and he was sent back to his office, and by killing Elizabeth, there is still one in rapture...? I don't know.
The ending of Infinite fades to black before we see whether the last Elizabeth fades away like the others. If Booker dies before the baptism, she should’ve faded away b/c he theoretically died before she had been born. But I’m guessing she didn’t fade b/c we have two new realities as a result of his death, one in which he was drowned and another new reality in which he wasn’t drowned and Elizabeth was born. If you have a reality in which he wasn’t drowned then you have the same two realities that exist in which Booker did and did not accept the baptism. It’s impossible to kill anyone or change future evemts when there are alternate realities for every action. Plus, I don’t believe we’re seeing the Rapture from the first game. There was a voxophone by Suchong in which he was complaining about Finck stealing his intellectual property. It’s a different Rapture from an alternate universe. Just a theory.
** Spoilers **
Okay, I have a theory about the ending. We learned at the end of Bioshock Infinite that two realities sprang from Booker’s baptism, one in which he went through with it and became Comstock and another reality in which he didn’t go through with it to become the Booker we played in the game. My theory is that their solution to rid the universe of Comstock by killing Booker before the baptism was flawed b/c the act of killing Booker also sprang two realities, one in which Booker was drowned as we saw in the finale to Infinite and one in which he wasn’t drowned at all.
In a world of multiple universes, it’s impossible to eliminate Comstock. Hence the ending to Burial at Sea.
First, above is a beautiful tribute to Bioshock Infinite that incorporated a number of early demos and cutscenes that did not make it into the final production. Very interesting.
Second, I’ve played this visually sumptuous game twice, and I have some thoughts about the story that might be worth sharing.