Finished it. Really fucking great game, I liked it a lot more than I expected and more than all the Souls games.
Played on keyboard and mouse, controls were quite comfortable and I had zero issues.
Combat becomes much better and more complex as you unlock more prosthetic upgrades, new skills, new combat moves, etc. I like that many bosses force you to use different damage avoidance methods - you have to parry some attacks, jump over others, side step, thrust counter, etc.
While Dark Souls games have a bigger variety of playstyles thanks to different weapons, ability to play as a mage, etc., I'd rather have one more complex and well developed playstyle like in Sekiro, because in Dark Souls games no matter which fighting style I chose the result was 30 hours of using one attack button and rolling around like Sonic the Hedgehog. That's why I never played any Dark Souls more than once, while I already want to start another playthrough of Sekiro to check the other endings (one of which has different bosses), but I'll probably wait till the DLC. Fighting things in this game is just so much more fun.
World exploration and finding different secrets was very fun and I really like the environments, they looked beautiful. I hope Nioh developers take notes how to make environments for Nioh 2 from this game, because as much as I like Nioh, visually it's quite ugly compared to Sekiro.
Some complaints:
Enemy AI is retarded especially when it comes to stealth. Enemies get stuck in random objects, don't react to me killing their friends from afar with shurikens, keep slashing their swords at the air while I hang from a ledge and cut their feet. I remember once I started trailing a group of several enemies in stealth and started backstabbing them one by one while the others didn't even turn around. Also once a boss just flat out stopped attacking me because I kited him too far from the tiny room with obnoxious camera angles the game expected me to fight him in. This has been a problem in every Souls game as well and is something From really needs to work on moving forward.
Too many recycled bosses. You fight the majority of minibosses at least twice and some major bosses twice as well (at least in the case of bosses they get some new moves).
Minibosses were pretty disappointing in general. Some are cool like the Drunkard and the undead wizard thing, which actually felt like bosses, while most felt like normal mobs with 2 health bars. Some barely had any moves. The centipede gimps have like 2 combos that they spam and that's it. The headless has a few different slashes and a ranged attack that he won't even use as long as you stay close to him. Fighting him is a chore and you have to do it 5 fucking times. The bull just runs at you, turns around, runs at you again. I would have exchanged all of this garbage for at least a couple of more proper boss fights, which were all a lot of fun except for the screen monkeys, which I wouldn't call a boss.
Some issues with combat responsiveness - for example sometimes I try to jump once after making an attack but the game doesn't listen, then when I press jump twice it queues it and jumps twice. Also, sometimes when I tried to deflect right after making an attack, the game interpreted it as me using a combat skill (which require pressing the attack and block buttons at the same time). I even had to "unequip" all my combat skills on some boss fights to avoid that.
Other than that, I'm quite happy. Hope there's gonna be DLC (the memory talisman is perfect DLC bait - just have Sekiro travel to different memories and fight people there) and/or Sekiro 2. Between this and Devil May Cry 5, March has been one of the best months for melee combat action games in a long while.