I love what you have here-- the room transitions are very smooth, the controls are nice, and the mechanics are easy to understand.
I'm a little bit thrown off by the mismatched pixel sizes amongst your assets, and I think a little more audio feedback from the attacks and enemies would do wonders for the atmosphere and immersion. But that's really anything there is to gripe about-- small things with aesthetics.
The game itself is wonderful! I'd love to see more enemies, more puzzles, more... all of it! If you continue to work on it, I think you have a very strong base for a great Zelda-style dungeon crawler! Keep it up!