Very interesting concept, I applaud your inspiration and dedication to this project, I gave it a go with my MIDI keyboard and it worked nicely (ignoring the part where I am missing a key on my keyboard...) as a technical demo it works fine but it still has ways to go as a game,.
The characters look really welcoming and it feels like the story may be fun and enjoyable to play.
The game looks really nice and artistic but it's also important to have in mind the readability of the menus and dialogue boxes, as well as the text speed, I would also have loved some background music so it doesn't feel as desolated when playing; As I mentioned in the video all of this is understandable given that this is a free indie game and also a DEMO version of it.
Hope I don't sound rude because that's not my intention at all, I did enjoyed the demo and hopefully my feedback can be useful.
I wish this project the best, I will keep tabs on it!
Keep the good work!