Just finished the demo as well and I like it a lot. The bosses are really enjoyable to fight and it makes me hopeful that we'll get even better stuff on this department in the full game. The level design is very similar to Nioh, with the addition of a jump button that gives some verticality but nothing out of the ordinary.
My second main complaint is that in both demo levels you are forced to have an NPC tag-along. I hope it's only for the first couple levels since they're basically the tutorial and the NPCs are your training wheels.
This is my only complaint so far. And I really, really hope that this is just there for this couple of tutorial levels, because playing the whole game with NPC allies would be a dealbreaker for me.
Edit: One thing that it's neutral for me so far is the reputation/morale system, that so far I just don't understand. I get it that if you die to an enemy it increases their level and make them harder. But the effect of morale on my character is unknown to me thus far.