I appreciated the unconventional upgrades and mechanics, the move set was strange and enjoyable. I do wish the eel enemies were a little more satisfying to fight, having them make use of the diagonal slash mechanic makes sense, but they ended up being more annoying than anything. Similarly, I wish the calculation for the slash angle of the eels and bubbles was weighted more towards the bottom of the player, it always felt like I had to be a lot lower than I would have liked to get an upwards slash. Other than that, everything felt responsive.
For the minimal visuals and sound, I think the game does a good job presenting an atmosphere, at least while playing I could imagine being some sort of mermaid princess trying to save her dying world or something similar (are you even a mermaid or just a ghost?)