Thank you a lot! As the one who made both story and music, I am really happy you enjoyed both of those!
Yes, the story is very much routed in traditional folklore. Sadly, we had to cut some content and it was originally thought that there were more nights and the story would progress every night when fetching the water from the well. It would then evolve around how the water changes Izumi and how Suiko tries to safe her sister, but actually hurting her by giving her the water. So thematically, it would be very much rooted in japanese folklore and be equally scary and tragic.
It is fairly hard to work together as a team outside of the jam and put in the additional time commitment, so it will be hard to continue on this. But never say never, maybe there is a way to continue the story somehow.