I always liked rhythm games, and I'm shocked how well you mixed it up with 'breathing' - very creative! Technically also well done, good job!
Only advise I can think of - maybe make the frog gain levels faster? Besides, great experience! 
Viewing post in BREATHWATERS jam comments
Thanks! I was going to make the bigger attacks make enemies drop more xp, but didn’t have time before the deadline. Also I had more enemies spawn faster, but it got a bit too overwhelming for the final boss. Did you reach it?
I’ll probably adjust those things in a post-jam version :)
Thanks for playing!!