I've been playing through Fez, and it's fantastic. It's rare these days for there to be a game that actually draws me in to the point where I am sorely tempted to neglect important stuff to play it, but Fez definitely has me in that "Welll...I could file for an extension on my taxes..." mode. Part of it is the fun puzzle-based game play, but I think more than that I'm just really grooving on the sense of place the game creates. Despite being a pixel-art inspired group of floating islands clearly built from several tile sets and designed as a series of puzzles, the world feels real and organic. It's not just that it's open to roam through in whatever order you'd like (with some exceptions) but also that through all the branching pathways and little structures and graphical touches within the game it manages to be something akin to an abstracted version of a walk in the countryside. You run across a clock tower, or a lighthouse or just a little glade with squirrels and chipmunks playing and it feels like visiting a real place in some abstract way.
Fez also lets you do this all at your own pace, with no enemies to worry about and puzzles that range from easy to brain straining. Want to power through a complicated room for a nega-cube reward? Go ahead. Prefer to go off in another direction pursuing cube shards and opening up more of the map? Go ahead. The world is yours.
What it captures best of all is the sense of wonder and exploration from childhood. Anything could be around the next bend and there are treasures just over the other side of the ravine if you can only find a way to get there...
This sense of exploration and wonder is something that's often sorely missed from games with budgets in the tens of millions and levels with extremely detailed textures. Those worlds should in many ways be more exciting to explore and experience, but frequently they feel like the clapboard movie town in Blazing Saddles rather than a real place. Yes they're detailed but they don't feel like there's a real world beyond them. By stripping away the enemies and time limits and just giving you a world to explore at your leisure Fez creates a sense of place far stronger and more memorable than most virtual worlds.
It's not that I need every shooter or even adventure game to be about traversal and sense of place, but there are plenty of RPGs and platformers that could take a few notes from the way Fez offers you an awesome world and lets you explore it at your own pace.