For those who know it better than I do:

1. Isn't it biased. In an infinite set of universes, there could be so many different splits, but this plot focuses on only 1 (the baptism). How come all the other possibilities of varying decisions were never an issue.

2. Anyone contesting that the ending IS logically possible?

The baptism is pivotal. Without it there is no Comstock.

The Baptism is what makes Booker or Comstock. And those are the only two realities that where visited.

And what do you mean by contesting the ending?

Except that makes no sense.

I'm one of the people who thinks the ending just *is* and doesn't merit dissecting at the level people are dissecting it, but to say that the baptism is the "pivotal" point in a game literally about infinity is an oxymoron.

And that's not even taking into account the fact that Elizabeth doesn't drown booker at his baptism. If elizabeth were to take booker back to the point of his baptism, he would be looking at it like The Ghost of Christmas Past taking Scrooge back to see his earlier self in his school days. Instead she takes him to a place where he, in first person, is being baptised again. He IS, inexplicably, the booker of the past. And when Elizabeth takes him back to that moment to drown him, the crowd and the preacher are not there. So, clearly, it's not the SAME moment. And she drowns a booker who has full knowledge of the entire adventure he went on with Elizabeth and who knew the horror of who Comstock would become. So why not just leave a fully aware booker alone? Because she saw that even with that knowledge he still could never be a good man?

play bioshock 2, as it's the exact same story in every single way. :)

It focuses on Booker from the 123rd "cycle" some very specific things happened in THIS cycle that made it special the first being that Lutece specifically pulled THIS booker into the time line and secondly Booker gets drowned effectively breaking the cycle. Secondly, don't try to apply logic to this.

If people are right and the "respawn" sequence is a random booker being pulled from a random reality and having his consciousness merged with the booker you were just playing, the "123rd Booker" concept is irrelevant.