I say its got holes because it introduces the conceipt of the multiverse and then tries to kill someone perminently from it. That doesn't work. As soon as you make a descision, the opposite will happen in a new and different universe. Also killing DeWitt, the one that has lived through the game and knows the consequences of Comstock also makes little sense.

That's not what happens. There aren't truly "infinite" universes in this, interestingly enough. There are lots of different realities but they operate within probability, not possibility. For instance "he doesn't row," from the beginning of the game. The Lucetes have taken Booker to the lighthouse many times and he never rows. Also, it's not "killing Dewitt," it's collapsing his timeline, essentially. None of the events happen because Elizabeth is cutting off all possible options. She's symbolically drowning DeWitt, that's not the "actual baptism" or all the other people would have been there. But I feel like if you're just basing this off a friend describing a game you can't quite have received the full picture, and that's quite alright.