it has to be Demon's Souls for me. I love how back then, Souls-like wasn't a "genre", Demon's Souls was just an exceptional action RPG with a lot of clever twists
I make game analyses on youtube:
FFVI: https://www.youtube.com/watch?v=mSO6n8kNCwk
Shadow of the Colossus: https://youtu.be/9kDBFGw6SXQ
Silent Hill 2: https://youtu.be/BwISCik3Njc
BotW: https://youtu.be/4auqRSAWYKU