(Xbox Live Arcade, $10) - 9.2/10
A delightful 2D platformer that takes place in a 3D world; you move in 2 dimensions, but can rotate the world 90 degrees at a time using the triggers to expose a new 2D plane to explore. The graphics are very old school and pixellated (yet sharp), with a very charming theme:
Your goal is similar to Mario 64; there are 60 cubes (like stars) in the game world for you to recover. Only 30 are required to "beat" the game, but it's more fun to try to find all 60. You'll encounter a lot of puzzles along the way, most of which are centered around the unique symbol language in Fez which must be translated into English to be read, as well as symbols representing controller buttons. When I couldn't figure out wtf the symbols meant within an hour of playing I took the easy way out and looked them up online, but for the determined gamer there is a rosetta stone of sorts demonstrating how to translate the symbols - you'll just be playing the game for a fair amount of time before you ever come across it, so patience is a must.
The only major problem in Fez is navigation; the many worlds/levels of the game are all connected through doors, and there are 5 specific worlds you can warp between using special warp gates. For the rest of these worlds:
traveling between them requires a good sense of direction to be able to navigate through multiple worlds to the nearest warp gate, warp to the gate nearest your destination, and then walk through a couple more worlds to get to where you want to go. Some worlds have 5-6 doors to other worlds, with no indication of which door goes to which world until you're standing in front of it. These worlds aren't all on your map to start with, so "explore the places I haven't been yet" is what you'll spend a lot of time doing, but once you figure out some puzzles and need to start backtracking to other levels to solve ones you couldn't figure out the first time you were there, this will be an annoyance.
That said, it's the only flaw in what is an otherwise very enjoyable platforming and puzzling experience, and for just $10 it's an absolute steal. Highly recommended.