Home 15 Min Experience! Geniunely good concept on it's own, rhythm game + JRPG seems like a very fun thing.
Execution is still raw and requires some polishing, it's just my personal experience with this demo though.
Beginning sequence seemed unintuitive to me, had troubles figuring out what's happening and what do i do. I understand it might be part of the plot, but still it needs more straight-ahead hints inside the game.
The rhythm game UI with the sequence of notes should be scaled differently. Due to notes being placed too close to each other i had hard time figuring out when to press it, IMHO good solution there would be to change the scale of that bar, so the hits would move faster but at the same time they would be further apart of each other.
Other than that, controls layout is quite unusual, especially "S" as action key was confusing, would be better if it was "Z"/Enter or any other more familar key. Same goes for the battle keys, due to them being the arrow keys its very easy to mess up. IMHO better solution would be to place them next to each other (ZXCV for instance or some other thing like that). It's way more memorable and gives less confusion.
Everything else about the game seemed brilliant, i loved the artstyle and sounds. If the game mechanics would be more polished and intuitive it would be solid 5 for me.