There's nothing quite like the sense of foreboding you get when exploring a new area in Dark Souls. Experienced players have had no way to recreate that—I know every inch of this game better than I know my own backyard—until now. Traversing brand new areas feels terrifying and wonderful.
Especially since the new content is just as good as anything in the main game. There are three big, new areas, including several bosses, new enemy types, armor, weapons, and spells. All in all it took me the promised 5-6 hours to complete, and left me feeling like I had just played the best kind of expansion—the one that somehow adds to a game that felt so complete already.