This is excellent, really enjoyed it, and I'm not even all that much of an anime guy. Played with both KB&M and controller, but mostly controller - Xbox One.
Footage of one fight:
At first I thought breaking posture wasn't worth it because of the low damage, but it makes sense if it's a boss rush game. And you can get some cheeky free hits in so its fine.
Hitting deflects feel really whimpy and made me not won't to use it that much. Some effects sound like a fucking cannon going off but deflecting is just a little tink. Flashier FX too, Sekiro being the benchmark of course.
Hits could use a little more oomph too, both on the enemies and you. Often I'd not notice I got hit. The hit sound sounds more like a glancing hit than a proper good one, could be meatier.
Sometimes the charge attack doesn't hit but I swear the sword is inside her fucking body, please...
Great performance, except for the 2nd phase of 2nd boss where it drops a lot. Mostly when inside the room, probably something to do with the smoke. Using a 3080 Mobile, with a weird display locked at 102 FPS.
My OS is in Swedish so some button prompts are fucked up, Shift and Space for example. If you're using the new input system you should be able to get non system specific button names I think. Needs rebinding too.

Some animations can use some improvements, the running ones are pretty stilted. But all the fighting ones are great, no negatives there. There's something odd about the sprinting animation, like her body keeps jutting back and forth, mostly visible with a locked on camera:
No victory message for the first fight, she just kinda lies there staring at the sky.

Something is wrong when using a controller moving at certain angles (I've checked too and as far as I can tell mine is working properly), gets jittery and slow:
But I still prefered it to KB&M, tried to avoid moving in those directions. Works perfectly with keyboard though.
The camera can be annoying in the 2nd fight, like its both too slow at keeping up at times and at other times its swinging around way too much. But FROM can't even get it right so uh good luck!
Not all objects get transparent when occluding the view, hard to see sometimes 2nd fight.
I completely missed that there were another set of abilities and played only with the first one, whoops.
The moveset is really fun and intuitive to use. Nothing bad to say about it at all.
Wall jumping can get very silly and you can endlessly roll around the walls in the 2nd fight. You can almost cheese the fight too if you get her outside in a corner and just spam jump. But most of the time she can get out.
Bosses are hard, especially 2nd one. First one didn't take that long. 2nd felt like she had some bullshit attacks at first but when you learn the fight it's fair I think. Really good job on the bosses, and they require a bit different strategies.
Now I just want more to fight. Great work.
Accidentally closed the browser once but I think I got everything...