Hi! I just played through Where They Fall and absolutely loved it. In terms of things I would add, I would just say "more". I know it's a cop-out answer, but there's so much potential here and I'd be really excited to see where this style of game goes if taken further.
I did notice that the runes fall in the same place every playthrough, and while it would likely be a programming challenge, I think some added physics-based randomness to where the runes fall would add a lot of depth and replay value combined with a longer narrative and more scenarios.
That said, I have no experience in game design, so I don't really know if these additions are feasible are not. Keep up the good work!