This was really dope! I was a little frustrated up front when I didn't understand stuff like the break meter or the mist, but as I explored more of the game it slowly answered all of my questions, and the answers were all cool and satisfying. I actually like locking some of the tutorial NPCs behind locked doors -- you get to talk to them before the last dungeon when all that knowledge really matters, and it avoids blasting you with too much tutorial text before you have any context for it. The guard and break stuff is a really cool and different way of thinking about rpg healing.
The last boss was a really hype stakes-raising moment after I felt like I'd more or less mastered the fighting. I know this is a demo, but just as an rpg mechanics/combat gauntlet this is already a really satisfying arc. I think you've got a really strong language here, and whatever story you wanna tell with it has the potential to turn out really cool and special.