Looking around online, I see that the main complaint about The Fountain is that its characters aren't well-developed. I normally care about characters, but I feel like the broadly drawn characters are appropriate here. This is a movie about universal ideas, and so the characters are, well, focused on the cores of those ideas. Aronofsky called his movie "a psychedelic fairy tale", and that's kind of what it is. It's almost a fable or myth in tone, and I don't complain that the tortoise and the hare need to be more complexly developed characters, my own attempt aside. :P