Can you change the outcome of the game's ending?
Solution 1:
No, which makes me feel a little bit sad.
There is only few cosmetic changes (for example with like with Cornelius Slate) but you can't change ending as far as I know.
From Gamespot forum...
Look up for the Gamespot Lounge interview with Ken Levine, he says that 2k wanted multiple endings but he said "nope".
Also you can watch on Youtube interview (4 - 6 min) how Ken Levine say that they wanted to "make player experiance that he had to make choices" but also he tells that this choices not change plot.