Echo is the "high art" of stealth-action games.

I just finished 100%ing it and I consider it to be one of my favourite games. The aesthetics are absolutely perfect. The main "echo" and "light/dark cycle" mechanics creates a completely novel and exquisite "push and pull" between the player and the game, and there is so much depth created from the finely tuned resource and action economy. The audio/radar "feedback" provides so much information to the player, allowing them to always re-evaluate their next move. It is a game of hidden meanings that draws me in.
I recommend it to anyone who likes its “fractal palace” aesthetic, with the caveat that the intro is 30 minutes long, and the gameplay itself gets repetitious. (also, setting the dialogue audio to french with eng subs was a great choice)