Eyes of the Stone Thief qualifies as a different kind of megadungeon, but megadungeon nonetheless. The dungeon is a living entity that eats places and buildings. Some of the things digested become part of the living dungeon making it larger and deadlier. The players are expected to spend a lot of time both inside and outside. When inside, it's about delving another level deeper and when outside it's about going on adventures and learning to hate the living megadungeon which stalks them.