Loved this game! Movement and combat both felt natural and easy to understand. The art was great and the music added a lot to the game, especially how the music was used as the timer for how long you had left in the zen mode. All of the enemies were really well designed and it felt quite fair. I think the UI was quite busy and it took me a long time to realise what all of the different health bars were and I still don't know what the green and red dots under the breath bar are.
I made it to the second big boss (the black ghost thing) but when I died there the restart wave button didn't work (I think there might have been another UI element blocking the button) so that's as far as I got. I wish I could have made it to the end to see what happened but I enjoyed the experience nonetheless.
I think the dramatic pace change when you take a deep breath is funny every time it happens and it's really well done. Overall an excellent game and I had a lot of fun playing, congrats!