To start, I absolutely love the overall art direction for this game! The atmosphere is a really good blend of creepy-cute, something which I personally find really appealing. The low-poly style really works well here, and having the stylized furniture to match the house is a really nice touch - it definitely feels like a well made environment! The music also adds to this, giving off a soft yet uneasy vibe. Overall really nice! Rei's model is also very cute and her design is very well made. I love her little hairclip and the starry motifs for her! (Kind of makes me feel like she would be revealed to be some kind of witch too, if the game continued past this demo). They way her eyes seem to glow in the rooms is very charming, too. I also enjoyed the first puzzle, despite its simplicity. The story definitely had me hooked - I'm excited to learn more about the origins of the house and how the witch trials relate to the overall story!
The major issue of this demo is the camera. The inverted camera for looking up and down vs the normal camera for looking left and right really threw me off sometimes. It is also quite finicky to control; I felt that the game worked better when the camera was fixed behind the player in the small hallway between the two rooms (when entering the last room, it would also get caught on the door and would allow me to see into Rei's model). Another issue I experienced is that I felt that it was not clear with what you could and could not interact with. I found myself clicking around the room hoping to see more dialogue or find any other items I could interact with.
Some other things I experienced which are more nit-picky than actual problems for a demo build. When trying to get the candle there seemed to be some kind of invisible object that was able to be climbed, and I also found this object by the correct painting (although this one was far less replicable than the one by the fireplace). I also noticed some issues in the first room with lighting Rei's model, at a certain point in the room she is far too overexposed. There were also some noticeable texture issues, which seemed to be a mix of both the room baking incorrectly and the shadow engine not functioning correctly.
I'm excited to see more if you decide to update this demo or finish the project to completion! It is very charming and the atmosphere is its biggest strength. Congrats on making a demo with so much potential!