In theory, couldn't you just have a program that reads your save files and tells you what you have accomplished? I know that this isn't the same really, but it would work. As long as people could find save files that have certain parts of the game unlocked (it would probably have to be story-related, though, or something that is actually saved) and other parts unlocked, they could put all of said save files into a program that would read yours and compare, then list what "trophies" or "achievements" you have done. It would take work and not actually get done since most people don't care, but it is possible.