Sorry if this was already discussed.
My idea is, that after the game ends, you get the the information, the interactive story, on how the world has changed since the main events.
I have seen this only once before, in Fallout 2.
After you finish the game, you are told the story of what happened with the vaults, with the cities, that Vic is now a farmer and has 5 kids and a dog, how and where the Chosen One ended his days.
I loved this in F2. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />