First playthrough: Died 5-20 times to every boss... except Demon of Hatred; that shit took me 52 tries (yes I counted)
Second playthrough: First-tried every single boss in the game... except the Demon of Hatred which took me 4
Sekiro is perfect; it truly does make you feel like a shinobi mastering combat. I've been chasing that high ever since that second playthrough.