MASSIVE WARNING: DO NOT, UNDER ANY CIRCUMSTANCES, READ ON IF YOU HAVE NOT PLAYED AND FINISHED BIOSHOCK INFINITE. EVERYTHING ABOUT THE GAME IS SPOILED BELOW AND DISCUSSED IN DEPTH. YOU HAVE BEEN WARNED.
OK so I noticed a lot of people are confused about the ending of Bioshock Infinite. Admittedly a lot is thrown at you at once in the last 25 minutes and you don't really have enough time to process or make much sense of it all.
I also want to point out that this explanation is also an actual ENDING explanation. I have seen a lot of people explaining the entire plot in detail, which I will also be doing, however they all seem to brush over exactly what the ending meant and how it was left. If you watched past the credits you should know what the true ending is, however if you didn't you will no doubt still be a bit confused. Basically what I'm trying to say is: don't worry; everything is explained here - not just the plot but the actual end too so if you want closure, then I guess just read this. There are a couple of things that I am a little unsure about myself, however these aren't massive plot points that really matter and either I just missed something or they are actual minor plot holes that weren't explained in the game properly. So, let us begin.
Let's start at the beginning. The basics.
Booker Dewitt, the players character, has been entrusted with the job of going to Columbia to rescue a girl called Elizabeth and bring her back to New York. Apparently, this deed will rid Booker of all his (gambling?) debts.
After blasting off into Columbia, Booker goes about trying to get to Elizabeth who is locked away in a tower. Before he can reach her though, he receives a telegram telling him NOT to pick number 77. He ignores it, not understanding what it means. He then sees a sign showing off a somewhat devilish hand with the letters AD printed on the back of it. These letters (AD) match the letters imprinted on the back of his, Booker's, hand.
The Prophecy Comstock, the ruler of Columbia, predicted that a 'false Shepard' would come to Columbia to try and steal their lamb (Elizabeth) from them. This false Shepard can be identified by the AD mark on the back of his hand. This false Shepard is Booker.
After going to watch the Columbia raffle on his way to the tower, Booker is told to choose a raffle ball, which he does. It is number 77 and he wins the raffle. His prize is getting to throw his ball at a couple of tied up villagers. After going to throw the ball, Booker's hand is stopped by a Police Officer who reveals him as the false Shepard. Now Booker must fight through hundreds of people just to get to Elizabeth and hundreds more to try and escape Columbia.
After he finds her things become pretty straight forward; escape this city in the sky.
It isn't until near the end that the plot heats up again. Before we go into this though, we need to take a look at Elizabeth's 'tearing' power.
Oh, off topic but it is also important to remember she has one of her little fingers missing.
Anyway, this tearing power was given to her as a child after the Lutece's twins experimented on her (she did not naturally have this power). The twins had previously made machinery that could open tears, however Elizabeth, after these experiments, could do it without any help.
Tears are basically otherworldly things. Other dimensions. A tear can be opened bringing in an object or thing from another world, or an entire world itself can be opened and entered into. However, and I stress this, new universes or items can't be created from scratch. They HAVE to already exist for them to be brought into either the current world or accessed in their entirety.
With Elizabeth's power out the way, let's move on.
Songbird, a massive mechanical bird that protects Elizabeth and can be summoned and controlled by a whistle flute thing, always seems to intervene at the last moment and take Elizabeth from Booker. When Songbird does this near the end, Booker goes on to try and rescue her. He hears, through mini tears in the air, Elizabeth being tortured and brainwashed into becoming the heir to the throne that Comstock wanted her to be.
After going through a tear into another dimension, Booker discovers an old, frail, Elizabeth looking out over a burning city. The chaos is her doing. She explains to Booker that this can never happen and gives him a piece of paper to give to the young Elizabeth. He then goes through another tear into a universe where Elizabeth is still being tortured and brainwashed. After rescuing her he gives her the note and all seems well.
They go on to find Comstock however after he (Comstock) tries to get Booker to explain why Elizabeth is missing her pinky finger, Booker kills him, denying any knowledge of it. Elizabeth, however, knows Booker knows something, even if he doesn't remember.
They attempt to escape, again, however they are attacked. This time by loads of Vox. Elizabeth then realises she can control Songbird by using his whistle. They use him to help kill the remaining Vox. Afterwards Elizabeth gets Songbird to destroy the Siphon; the original source of her power and a device that forces her to remain within Columbia and stops her opening up another dimension to escape into.
After it is destroyed, Booker drops Songbirds whistle because it becomes electrified and panics as Songbird rushes towards them, no doubt about to flatten them both. However Elizabeth opens up a tear into another world, allowing them to escape. This world is Rapture.
As they wander through Rapture they then leave through a lighthouse door and come into a huge, massive, open, infinite space full of never-ending lighthouses.
This is where the explanations start.
So each lighthouse represents a world, a dimension. What are these dimensions? Well they could be anything, worlds never even heard of, but they are also the outcome of every possible situation and choice.
So, for instance, if you decided to stay at home (and play Infinite lol) rather than go to work, another dimension would be created for where you didn't stay home and you did go to work. A new world is created for everything that could have ever been.
We then learn, by going through one of these lighthouses, that after killing thousands of African-Americans, Booker went to get Baptised to rid him of his sins, however he refused the Baptism at the last moment and went on to live his life. Booker and Elizabeth move onto another lighthouse - another thing that happened in Booker's life.
We are now in Booker's apartment, and there is Robert Lutece standing in the doorway. You hear a baby called Anna in one of the rooms and after entering it, you see a very young child (Anna) in a cot. Booker denies frantically there ever being a child, completely confused as to why this is happening. But to continue he must go through with the scene how it happened before. He hands his child over to Robert who then leaves, saying something along the lines of 'Mr. Comstock forgives your sins' or something like that. We then go to a scene where we see Comstock holding Booker's daughter as he is about to go through a tear into another dimension (the dimension of Columbia), however Booker tries to stop him leaving, begging for his daughter back. Unfortunately Comstock gets away, however he isn't quick enough and as the tear closes Anna's little finger gets caught in the closing tear and gets cut clean off.
It is now obvious that Elizabeth, previously called Anna, is Booker's daughter.
Now this is where it gets a little confusing. Booker realises that the Lutece's twins, who, I would like to point out now aren't actually twins, are just versions of the same person from different dimensions who met each other, came to help him after they were betrayed by Comstock. They came to help him get his daughter back from Columbia.
They opened a tear and brought him into the Columbia dimension. After bringing him through, Booker's mind created new memories in place of the old ones. He created a new purpose for himself in this other world, and this purpose was what he wanted to do all along: find Anna/Elizabeth and get her back.
Unfortunately it wasn't as simple as that.
Before entering the final lighthouse we hear Booker saying about how they will just go back and kill Comstock in his crib to prevent all this, however that actually means killing himself as you see in the next section.
When, in the original dimension, he rejected the Baptism, another world was created for if he had accepted it. This is the place they are in now. This is the world where he accepted the Baptism.
After being Baptised, what did this new, free of sin Booker do? He called himself Zachery Comstock and created a city in the sky called Columbia. He was born again but this time an evil man.
To kill Comstock when he was born, Booker has to kill himself when he turned into Comstock. And that is at the place in another dimension where he accepted the Baptism instead of rejecting it.
Lots of Elizabeths appear and they proceed to drown Booker, presumably in the Baptising basin. After he dies we see all of the Elizabeths disappear.
Now that is the end. The credits roll from there. HOWEVER, there is more. I will go into this after explaining all of the above, though.
So you might be wondering, generally, what all that meant.
When Booker was first faced with the choice of a Baptism, he declined. He then went on to have a baby. Obviously another dimension was made for if he had accepted the Baptism, in which case he then became Comstock who created Columbia. Both Comstock and the original Booker existed within their own dimensions, doing their own thing. However after Comstock needed an heir but couldn't have a child because he was infertile, he used the Lutece's twins tearing machine to take Booker's own child, Anna from him. Technically, because Comstock is Booker but just in another world, Anna is still biologically related to him. Booker actually sold Anna to him to pay off his depts to him, and I know what you are thinking: isn't there just another reality for if he HADN'T sold her? Well, yes but also no. Because Comstock wanted - needed in fact - Anna so badly (and it could be only Anna because she was the only child related to him) even if Booker hadn't sold her, Comstock would have entered Booker's world and taken her by force. There is no world, while Comstock existed anyway, where Booker and Anna stayed together.
Booker was caught in a never-ending cycle of trying to save his daughter. He had already been to Columbia over a hundred times before. This is proved when he is in Columbia and asked by the Lutece twins to flip a coin. He does and it is heads. They mark it on a chalk board under 'heads' and you see that there are tons (over 100) of other heads markings on it. No tails have been marked down. This means that Booker has been there over 100 times before, flipped the same coin and, as always, had the SAME OUTCOME. While you can choose, during the story, to kill someone or let them live, that is a choice (no doubt another world is created to accommodate the other choice you had) and not chance. Flipping a coin is chance. He already flipped the same coin every time he had been to Columbia before and, as always, just like all the events there, it was scripted to heads.
Back to where we were before, though. It didn't matter what happened, he would always end up where he was. It was IMPOSSIBLE to avoid. Because Booker had a daughter and Comstock needed her and he made their dimensions cross and he took her, there was NO OTHER dimensions with a different outcome. Every world Booker existed in ended up with him losing Anna and going to save her. A never ending-loop.
HOWEVER, it does end, here. After Booker accepted he needed to die to kill Comstock, he allowed Elizabeth to kill him. By killing himself at the point in time where he accepted the Baptism, he killed off ANY POSSIBILITY of a Comstock. Comstock never existed. Comstock never came and took Booker's baby and Columbia was never built. Anything Comstock had an effect on or had anything to do with was destroyed and never happened.
This is where a lot of people lose it. They think Booker, Comstock, Elizabeth and Columbia ALL died, but they didn't. Booker didn't kill himself when he was first born; he killed himself when he turned into Comstock. All that did was kill off any Comstock version of him that there ever was.
After the credits, there is a little, tiny section, where Booker wakes up in his apartment and hears Anna crying. He goes into her room and calls out "Anna?!". That is where the game really ends.
This little part backs up what I am saying.
Because only Comstock was killed and stopped from ever existing, the Booker that declined the Baptism STILL existed. However because Booker and Comstock's worlds crossed, all parts of Booker's life that included Comstock or anything from the Comstock dimension itself was removed from his life. There were no Lutece twins who came to collect his daughter, no Columbia, no Comstock and no adult Elizabeth in his, or any other dimension ever. He then went back to the last time in his life that was free from Comstock related madness: him in his apartment with Anna as a baby before he met Comstock.
Now people may come back with "But Elizabeth disappeared from the scene after drowning Booker", and while this is true, it makes sense, and is also one of the most depressing parts of the game, despite its happy ending. Elizabeth in that form never existed. The girl you went through the entire story with? She never existed. Anna IS Elizabeth, but because every outcome of baby Anna's life was to end up in Columbia with Comstock in that tower and grow up there, when Comstock died and everything he had done and he had effected died with him, the adult Elizabeth also went. There was no adult Elizabeth in any other dimension that Comstock wasn't in. Because he was in every world she was in, when he died, the adult her died to, leaving only baby Anna. This means that while Anna will be free to live with Booker, she will never turn into the same person. She will never be able to open tears as that was an ability given to her by the Lutece twins in Columbia, she will probably never be able to pick locks (why would she need to learn to do that?) and a lot of her personality that was influenced by being in Columbia will be different. She will never be Elizabeth. She will always be Anna, a completely different human than the one we got to know. So, in a way Elizabeth DID die. That, to me, is a very, very, very depressing thing indeed, as Elizabeth was an incredibly crafted character and the best female character in any game I've ever seen.
Another quick thing to note, that some people may mention, is: why did they bother to stop Comstock at all? Why not just change what had happened by going back to old memories and parts in time through those lighthouses? The thing is that they can't. When you go back to previously, already, made memories, you can only relive them, you can NOT remake them. Booker couldn't go back and choose to run off with Anna, because his decision to sell her was made and he HAD to go through with it even if he went back knowing it was wrong. Even in an alternate reality where he DIDN'T sell her, Comstock still came to steal her away.
Now, the only slight odd thing about this is: if you can't change already made memories and situations, how did he allow Elizabeth to drown him and kill off Comstock if that ISN'T what happened? Well, while Elizabeth was not in his memory, and could not effect proceedings to do with other people, you'll notice she can still touch and interact with Booker. So while her control over the entire, overall scene is limited, she can kill Booker in that scene herself, and end it there.
So there you have it! Ask any questions you want in the comments and I will try my best to answer them!
Quickly; if you want a summary of what happened minus the confusing shit: Comstock was Booker in an alternate reality where he didn't decline the Baptism. Comstock took, either by force or through buying, Booker's daughter Anna (also Elizabeth). Booker went on a cycle of trying to get her back that never ended and always ended up the same. In the end, he let himself be killed at the point where he turned into Comstock and thus everything 'Comstock related' died. He became himself in his last pure, Comstock-less memory, which was him with baby Anna. The end.
P.S: A quick note I forgot to mention: The AD on Booker's hand stands for: Anna Dewitt. Comstock foresaw Booker coming now doubt because he knew he would try and get his daughter back because he never wanted her to leave.