I've played part of the demo (didn't get to finish it yet), but I wanted to say that this game looks really promising! The environment design is beautiful, the grappling hook is pretty fun, and I'm already hooked on the story and lore.
One serious point of critique, though: some of the lights are extremely bright and disorienting. The flashing lights that burst on my screen as I was attacking a ghost were actually a little painful.
Also, I understand that this is just a demo of the prologue, but I was disappointed that the game didn't save my progress when I chose to briefly return to the main menu. I wanted to keep playing! I'll have to try it again later.
Also, I wish there was a way that I could access my items. I injured my character after jumping off a cliff (because of course I had to check if there was fall damage), and I didn't know how to drink any of the health potions. (It's possible that the game covered that later in the prologue, but I didn't get there.)
Meeting an otter was nice, too!
Overall, though, this game is pretty fun. Keep it up!