Antichamber level 1:
https://www.youtube.com/watch?v=18Pd-uEVVVc
I think that the first puzzle of Antichamber is very good level design, it's a very simple yet hard puzzle. I think it's good, because it sets up the game perfectly.
This puzzle teaches the player that this game is all about unusual optical illusions and trickery and prepares the player for the next unconventional puzzles the game has to offer.
The first level of the game doesn't follow the conventional rules of puzzle/level design, yet it does. It doesn't follow the rules, by clearly only having only one way to solve the puzzle and that's the way the designer intended the puzzle to be solved, some would argue that this isn't a "right" way to design a level and I agree, I think that player's should be lead throughout a game without noticing that they are lead or guided, but in this game it works, because it gives subtle hints by places coded messages on walls. This game is all about breaking the conventional, these little hints are part of the rules of level design to "guide the player". this is why I think The first level of Antichamber is an example of very good level design.