I'm going to mention this now since some people have brought it up. While a neat idea in concept, and maybe worth exploring it again with a better fleshed design, World / Character Tendency is absolutely trash in Demon's Souls. If you played online, you were at the mercy of the average Tendency of all the players; if you played offline, good luck figuring out what changes what. Enjoy all the blocked events/loot/characters due to navigation through a neutral/not pure tendency. Seriously, I hated that. It's a mechanic that I haven't missed at all in any of the other games.
I'm not sure if it has been said, but the whole "you gotta die" prologue was also great and probably the best intro in all Souls, even if it is shitty that instead of an impossible battle they just throw you into a "lol killed" cutscene at the end.