Something weird happened to me the other month and I installed the Steam client on my Arch Linux system. I wanted to play some games and decided it was time to take a risk and perhaps spend money on a game rather than placing all my hopes in FLOSS games - and never playing games.
I saw Portal was on offer for... I don't know... under £3 and I'd long wanted to play it and play it I did and enjoyed it. Then I moved on to Portal 2, and while I did not share the enthusiasm of some about some aspects of the sequel, I did overall greatly enjoy the puzzles in Portal 2.
I tried a couple of other games and decided first person puzzlers were my thing and to look out for others. This is when I encountered what I am currently thinking is the best game I've ever played: AntiChamber.
AntiChamber is the king of puzzlers. You're thrust into a world about which you know nothing, save perhaps that it will play with your mind. One reviewer said "you don't play AntiChamber, AntiChamber plays you". It's said to be a pyschological exploration game but I'm not so sure about that. It's definitely a puzzle game, but frequently it is unclear what the puzzle is.
There are some really nice touches in the game which I wouldn't want to spoil by revealing them, but they basically reside within the way the game evolves or progresses, and reveals new concepts about the world in which you're trapped. Presumably trapped that is - it seems you're very safe from harm - so progression is less about escape and more about solving puzzles.
This is where it contrasts with Portal 2. In Portal 2 I sometimes found the story irritating and got in the way of me doing what I wanted to be doing, and that was solving puzzles. There is no over arching narrative as such in AntiChamber, or maybe the story is just highly abstract, which is one of the game's beauties; it arrises through the player's exploration of the world and their progression through it.
Really, everything about the game progresses. The sound eventually becomes music, and the jarring graphics which initially are stark white and primary colours reveal subtleties. It's rewarding game to play.