I love these oldschool styled JRPGs! I think this has a great chance for commercial success so I will give you all the feedback I can think of.
Graphics/Audio was very pleasing, you did a great job on that front and I have nothing to say about it. I especially liked the animation.
I thought the gameplay loop for this demo was a little repetitive, since the enemies were so weak there was nothing I needed to do besides spam the attack key and wait for them to die. I think it would have benefited from higher jumps of difficulty between combats.
I liked the circle animation that tells who gets initiative when taking turns, but I think it could be tuned up a bit to be faster because I didn't like waiting so long between rounds. I have a similar attitude towards attack animations, it would be nice for them to be sped up a bit more too or at least have the option for it in settings.
I think you did a good job with the UI, everything looked crisp. I think enemy health bars need to be added though, it's important for this kind of strategy game so the player has more agency with how they want to approach the fight.
Overall, your game is really shaping up and I can't wait to see it on the Steam store! Good luck!