What a delightful little game! Definitely one of the best entries.
I really enjoyed the level design and the controls. The moment you get the sword feels really rewarding and the story surrounding the gameplay is giving me very cozy vibes.
Art and sound are also well done, but I think you could push them even further. You could add some more variation to the textures you use, as they look a bit repetitive, and some more saturated color highlights could also look cool. Another suggestion would be to add some indication of light in the scene. You don't have to go all out, but I think adding some dark gradient effect towards the end of a screen could make it fell a lot more like a dungeon. I'm thinking about something like they have on the ground in this image: 
Of course, all of this is also a style-choice and personal preference plays a big role.
And again really strong entry, despite minor nitpicks.