That was interesting! The story and setting are charming, and the concept has potential. The difficulty is a bit imbalanced, but it's not frustrating.
The artwork is a bit busy. The tutorial level is okay-ish; the plainer background is easier to distinguish from game objects (although the stones look very similar to the walls). However, the main level's background is quite busy, and it blends many of the items together.
All-in-all, good work!
[EDIT: 8-21]: Oh! I almost forgot: the coin sounds can stack on top of each other quite quickly, causing a harsh audio peak.