I don't think I can call it my favorite game, but everything is made on the highest level:
ㅤ• complete freedom of actions (multiple ways to complete a mission without any punishment for doing it the "wrong" way or coercion to the "right" one);
ㅤ• an elaborate combat system (whether you're into stealth or not, you'll find your own style);
ㅤ• side activities (I really enjoyed the side quest and optional objectives);
ㅤ• attention to details (sometimes I made the stupidest things just to check whether the devs have foreseen that, and to my pleasant surprise, most of the time, they have);
ㅤ• an interesting plot (and some deep lore, although, I didn't really look into it, but that's an advantage);
ㅤ• all characters, even minor ones, have a personality, and in addition, lots of interesting NPC dialogues you can eavesdrop on that may tell you more about the setting;
ㅤ• beautiful locations (I genuinely loved to explore them even when there was no loot) and unobtrusive soundtrack (it sounded nice and set up a perfect mood).

Basically, it's a great game with lots of content if you're really dedicated to it and don't just run straight to the main objective ignoring everything else on your way. Perfect for people like me who just have to explore every nook and cranny and love to be rewarded for that.