I thought I’d check out the new Sekiro boss rush mode real quick last night and ended up in “one more try” mode and (unwisely for my sleep schedule) challenged Inner Genichiro until 4am. They kept it a little bit secret that this update added new variants too, it was a pleasant surprise. Even though the new Genichiro is about as hard as vanilla endgame bosses, Gyoubu and Butterfly are more timesinks than actual challenges, and G’s big new move is actually very punishable so I’ll get him sooner or later. The main thing the boss rush context does is you need to demonstrate a high level of consistency, beating bosses 10% of attempts is good enough to win Sekiro normally, but now you really need to prove it’s not just luck.
The first rush seems a bit intended as practice for the second, main rush which I’m terrified of. It’s like 10 bosses and the next-to-last is Sword Saint, and the last one is a mystery boss (I would guess it’s most likely to be a variant of Owl Father, especially since “Inner Father” makes thematic sense as a boss name, but they might surprise me). One thing I learned from the first rush is not to waste time ahead of time practicing against who I expect to be the final boss, as the variants punish things that work against vanilla so your first run to the end is guaranteed to be toast. And it let me practice super Genichiro as soon as I revealed it once.