I just beat the game (saving all the little sisters, of course!), and I have to say I found the ending to be missing something.
It’s revealed that your character rescues the Little Sisters (Yay!), and appears to die of old age many years later, albeit surrounded by the now grown up Little Sisters. But… Isn’t your character technically immortal? He’s full of Adam, can shoot lightning, fire, and ice from his hands. A very touching ending, but personally, I would have liked an option to save the Little Sisters and re-build Rapture- maybe develop a cure for the Splicer’s condition, even, so they could be normal again?
Oh, and if you pay attention, you find out that Rapture was completed on November 5th, 1946. (there’s an architect’s model of the city with that inscription in many of the Bathysphere stations, including the one you first arrive at) It’s clearly mentioned several times that WWII happened, so that does kind of make you wonder how Ryan managed to build an undersea city in the middle of the Atlantic Ocean, with with all the U-Boats and the Sunderlands and Battleships shooting at each other…
How did they even build Rapture in the first place? Not just physically (the technology to do so doesn’t economically exist even today, never mind in 1946), but there seem to have been at least 10,000 people down there… you’d think word would have gotten out, especially after a decade or so.
Rapture is a huge place (there are maps on some of the walls which hint at other significant areas that you don’t visit in-game), so you’d think there would be at least one area where the survivors are still "normal’, so to speak.
Having said all that, it was still a great game and I enjoyed it immensely. I’m going to play it through again and go exploring this time, to see more of the city and try and find all the diaries etc. As others have said, it’s incredibly atmospheric- the whole Art Deco/Retro 20s-50s look is incredibly appealing and very, very believable!