One thing I've noticed in roleplaying, looking at the "dungeon" is a really common playing device. And why shouldn't it be? It can be both sprawling and vast, and limit the movements of the players without making them feel boxed in. They can feel as though they have a multitude of directions they can travel, but at the same time, their basic choices are limited enough that a DM can plan out what they'll face ahead of time. The depth and variety of a dungeon is limited only by how much time a DM is willing to devote to it. Because it's not just a big open field, the players never know what will be around the next corner.

Unfortunately, I feel like they're limited in a stylistic sense. Generally you find either the classic dungeon or labyrinth, or the more natural cave (perhaps spiced up by the presence of crystal, mining tools and carts, ice, lava, or so on). Lately I've found myself trying to think up alternatives to the "dungeon" setting, with the same core construction (limited paths, 'rooms' or some other substitute that does not allow characters to see into an area until they've entered it). The problem is, if I stray too far, I wind up with 'walls' that can be circumvented (trees to be climbed, obstacles to be torn through, etc). Does anyone have any ideas?