One of the toad sounds is louder than the others, but I saw you've already addressed it in the comments. I wish the blood drops would give you a tad bit more health, it made the fight quite difficult, but that might be just me.
Other than that, I had fun playing! Good boss design and art, the particles and UI can go unnoticed sometimes, but I see you've put in a lot of work with them as well. Thanks for the experience =]