Game's crap, utterly overrated. Here are my points.
For context, I tried to endure through this game and gave up on it 4 times completing only one boss,
on the fifth try i finally could make it, got through all of the bosses in 5 or less attempts with the demon bell enabled except Corrupted Monk which took 10~ tries and Isshin the Sword Saint where i had to turn off demon bell in 20~ attempts.
1. Gameplay.
People say it's fun and it's a rhythm game, i can agree on the rhythm part except it's without music and completely relies on combo memorization, play osu!mania without music and just memorize the combination to complete the map, not very fun.
And when you get hit it's usually 50% and up to 80% of your hp, which decimates your posture which forces you to sprint from the boss to heal and start building up his posture all over again. Sure when you memorized all attacks it looks and plays fun, pity thats like 2% of total gametime. If you don't wanna die and game highly incentivizes you to try to hang on to your life by taking half of your current skill point progress and half of your money WITH NO MEANS TO RETURN THEM and occasionally inflicts Dragonrot which is completely unnecessary and useless mechanic when you can literally cure it for 200~ sen, it's just annoying hassle, sure it's not impactful and i had to only cure it once, but why have it in the first place?
So if you don't wanna die you try to play most efficiently, right? The problem is the most efficient tactic is to cheese the ♥♥♥♥ out of the enemies, for example, early in the game you encounter chained ogre, most of people had troubles dealing with him initially myself included, and what's the most efficient tactic to beat him? You kill the guards, aggroe him, go away far enough and deal a stealth blow, half of the work done, but if you die and do all the steps all over again repeteadely, this gets annoying really fast, you basically have to do 30-60 seconds of prepwork each time before an actual attempt and it happens too frequently in this game, Long-arm centipede Sen-un, where you have to kill 5 smaller centipedes each time while boss is also trying to kill you while youre at that, and not dealing with them isn't an option either, gank fights are nearly impossible in this game, runbacks to mini-bosses who are frequenly harder than the actual bosses are terrible in this game. In boss fights you also are incentivized to cheese them, you find one or two moves where you can deal damage, do so a couple of times so their posture breaks at an adequate pace and do this process 2 or 3 three times, depending on the boss, alternalively you bash your head against the wall 10 or 20 times so you perfectly guard his every move, i can't find this fun. Also you only get one weapon and most fights are 1-2 attacks, deflect, 1-2 attacks, deflect, 1-2 attacks, boss makes his "black-flame-360 degree-way of the phanthom dragon-mortal strike" move while you jump on his head, deal 2 attacks and all over again.
I don't understand the praise for the Isshin the Sword Saint fight, boss has 4 healthbars and 3.5 movesets, this is just toxic difficulty, basically your prepwork is first two healthbars which ideally last 60 to 90 seconds and then difficulty spikes rapidly, you just try to memorize the moves little by little every death, how is this any fun? Spending minute and a half to get to the actual boss is bad design, real difficulty is your mental state, i felt exausted at the end of the fight, i didn't feel like i've beat the odds and overcome the challenge like i did when i beat Malenia (no spirits, no freezing pots, two-handed Nagakiba, 120~ lvl, if you assume i didn't fight "the right way" or that im a casual, i would argue not). Okay enough of the gameplay, i already wrote too much.
2. The World
Sure the world looks beautiful, but i got kinda bored of it and sometimes lost (namely in Ashina Castle) because of the repeating architecture, i feel like there could be more variance, subjective, not a big flaw.
The enemy placement, it's bad, like, you place 5 F***ing okami warriors in the same place? How are you supposed to fight them? I wrote about gankfights earlier, i don't think i could take 2 in a fight, and you place 5? Theres also a moment in foutainhead palace where you encounter 2 nobles and a lightning naginata okami warrior in a wide corridor and no means to run through them or get around them, the problem is this warrior doesn't chase you in a safe place from nobles and one of the nobles is behind a fence which makes it impossible to kill him from a distance, it makes the encounter very annoying and painful. Or the s**tton of Fencers in ashina castle, difficulty just for the sake of it, basically you have to cheese again or just run through them which i started to do at some point, there's just no reason to fight common enemies, considering the effort and reward.
3. Customisation
You get NO cosmetics for your character and your only weapon, until you completed the game and beat gauntlets,
even Lies of P, which gets too much hate i feel, has some limited customization and it's enough to freshen things up.
It's not a major flaw of course but i got a little tired in the end, you don't get the feel of progression, you're the same ragged shinobi as you were at the start of the game.
4. Movement
It feels slippery and i felt like i couldn't rely on it, especially catching ledges and inintuitive seemingly random grapples.
I played on the MnK for the context, maybe it's better on the controller.

The game is good, but i wouldn't recommend it in its current state. I didn't see any changes since demo version, so it still lacks its promised content, the gameplay is quite repetative and there is no main storyline to justify it, only small stories from customers, but there are few of them and they're not very interesting. Just wait for the full release.

I dont usually write reviews, but this game failed my already low expectaions so bad i just couldnt pass by.
Since its SOULS-like game i will compare it to the Souls series and Sekiro.
1. The Port
It is bad, so bad i think they gave the job to an indian freelancer for 5 bucks. I doubt anyone will get any enjoyment
playing on keyboard and mouse, it feels like an emulator, twitchy camera, only controller icons, bad default controls layout.
And no, "just play controller" doesnt work here, i find KB the most comfortable in any type of games, except for fightings and platformers, because of its accuracy and more keys to press simultaneously. KB works almost perfectly in ds3 and sekiro, but not there for some reason.
Optimization also lacks here, i get around 70 with some fps drops during fights on my rtx 2070 and ryzen 2600, what i dont think is normal.
2. The Game itself.
Cant say much, because i want my refund.
The balance is weird, you need to skip the 2nd mob you encounter, and simple samurais 2-shot you, so you must cheese them and kill one by one, it all just for the sake of being difficult, i personally dont like those measures.
Fighting is monosyllabic, attack-block-dodge with a strange mechanic of Ki.
And finally the colors, there is no common theme, all this yellow-black-purple-red psychedelia just feels cheap.