[Bioshock/SPOILER THREAD] The feels.
The ending hit me like a rock to the face. I had my doubts that erasing DeWitt from the timeline would stop Comstock from ever happening because Novikov's self preservation clause.
K then pointed out that ONE Anna remained, and so the curve closes restarting at "point zero".
After much rumination, I think that one timeline survives: the one in which DeWitt gets actually baptizes. And Anna knew it. Booker was in the "main" timeline, the one that cannot be erased.
Because doing so would invalidate the "main" Elizabeth and thus implode the loop in a flashbang of Paradox.
The circle has not been unbroken, after all. No freedom, no choice. I ish so sad about that, but it was awesomely narrated from start to end. Hats off and a tear of regret.
there is a very detailed thread about all the possibilities and the possible paradoxes in NeoGAF
I prefer to go with: Drowning booker causes the possibility that Booker accepting baptism and becoming Comstock always winds up in a paradox.
The universe goes, "No", wipes those timelines out, and only allows timelines featuring baptism rejection to exist.
Hence the post-credits scene.
But that's just the optimist in me. As mentioned before it is as happy or as sad as you want it to be.
It is also entirely possible that once the siphon was destroyed, Elizabeth became like the Lutece's: able to exist across space and time, and therefore outside of causality.
Therefore killing booker before he becomes comstock only eliminates a select group of possibilities determined by god-elizabeth.
.^ THIS
god-Elizabeth zeroes out the possibility of comstock, but is at that moment, immune to paradox. That or she sealed herself with the comstock multiverse.
walking the pattern does that. LOLOLOL.
Harold
says
I remember speculating on that. HAHAHA
also... fucking bioshock 1 wrench!
From the reddit thread: She doesn't simply kill Booker before he becomes Comstock; she does it after the variable in which he does swings in that favor.
More specifically, she does it *after he choose to accept the Baptism.* She breaks the cycle, because if Comstock does not exist, neither can she.
All that remains are the realities where Booker rejects the Baptism, with the only lasting effect of Elizabeth's action being that Anna is never sold - hence the scene after the credits.
... i read the neogaf thread. DLC WITH SONGBIRD IN IT OMG (sorry...)
Elizabeth effectively turns a variable into a constant. But again, that's one way of looking at it. The "choice" on how to look at the coin, is up to you. 
"smothered in the crib" after he was born.
Also: None of the Elizabeths that drown you have the Bird or Cage necklaces that you pick for her. She isn't "your" Elizabeth. Even booker notices that.
DUN DUN DUN DUUUUUUUUUUUUUUUUUUN
Read the thread idle_eidolon posted. Food for thought, but still thinking that the worst timeline remains active (Booker -> Comstock).
^ then, we have DLCs.