Puzzle games are all about problem-solving. You hit a new obstacle, get lost at first, go through an individually unique process, and then come up with the right solution for the problem. The real trick is to make me work on the actual dilemma in the background, using the earthbound trials as puzzle pieces, going out of bounds of those simple steps (which is true for the gameplay as well!), and building up to the bigger picture.
I simply adore the way The Talos Principle directed my attention to the grand philosophical theme of humanity and its nature, started an infernal, internal struggle within me, and later on, made me accept it instead of solving it. It might sound corny, but it's just what happened because of the excellently thought-out message.
I felt like I was opening my eyes for once, finally seeing the new possibilities, which is exactly what I'm looking for in such a game. It's a literal room to think that everyone needs.