Like a 2D top-down action game, the game feel exciting to play. Controls are snappy easy to understand. The level design is quite good also. I didn't get to finish all levels due to getting killed and losing all progress. I don't particular enjoy losing all the progress that have been made after getting killed. It just frustrates me that I have to do it all over again.
I like using all the abilities, I wish there is a keyboard shortcut to toggle abilities. If there already is, I just missed it then, a quick pop-up will do great. The flute magic to make the water enemies vulnerable is too short. And I don't feel there's any change to the upgraded sword. I wish the sword range become further though. But, all in all, I feel all abilities have their appropriate purpose. During Skeleton Mage boss fights, I use the bomb and running around lot, it is very satisfying to hit multiple enemies at once! (Kinda wish the blast radius is a bit wider too though)
Since you are planning to make this into a commercial project, I will comment from a potential buyer's perspective. There's currently no motivation (or hook) for me to want to buy it. For this kind of game, there must be a compelling motivation behind, a simple short story at the beginning of the game would do the trick.
Since this is very similar to Link's Awakening or Binding of Isaac, I would rather just play those games instead due to the level of polish. Binding of Isaac is appealing to its unique artstyle and theme. While Link's Awakening was very early to market and they have high level of polish quality. So, to make me interested in buying, you would have to (a) have a unique theme with compelling background story; and/or (b) have higher level quality of polish compared to existing games in the market.
But this is me, other players may buy the game for other reasons.
But the base of the game is there. It's still in a very early stage to be an appealing commercial project. You should work out the appeal factor for some time first.