What a heartfelt game!
The art is impressive - custom stuff through and through, used well to tell the story. Same goes for the sound effects.
While the gameplay is mostly just going from story point to story point a la walking simulator, I appreciated having the mine cart puzzles to keep things interesting. I also liked that when I messed up and fell down a hole I was instantly restarted back at the beginning of the area, and not have to load a save. Maybe not terribly challenging or deep, but appropriate for what you were going for.
The game didn't feel like it overstayed its welcome, either. Just enough length to feel like the story was told without too many shortcuts, and still not feeling like it was dragging or trying to pad itself out.
While this isn't the type of thing I'd normally play nor would I enjoy it for long, I respect the effort it took to craft this experience and liked what I saw. Well done!