Neat little game!
I liked the style and it was an interesting locked door / key puzzle once I understood the instructions. Was a bit confused first and some might have been fixed with wording, but also placing of the instructions on the tile you were supposed to stand on for the first such door could also have helped.
Fighting was nice too, the boss got bugged though so it was very easy, though it did start out a bit too unfair with a huge amount of egg thrown at me before I could get my bearing.
I think its door could have been triggered by stepping off the stones onto the mud/soil.
Movement and exploration was nice and the hidden walls had about the right difficulty!
Playthrough: https://youtu.be/qp1oZ50Llnw