On the one hand, a cool idea to change platforming, with the added value of the mechanic being all purpose (needing to wait to have enough air to move, but not too much because you will blow up, and using it to move and to kill enemies).
But on the other hand... the controls really frustrated me. Most of the time I am unable to move, which lives me to the mercy of sometimes pixel perfect angle shoots. And while it took me a few tries I did finish everything up to level 3-3, where I really felt that luck was the biggest factor in surviving.
Also, there were a few little bugs (such as after every camera shake from being hit by the blue balls the camera stays a bit zoomed in [and it got to the point where I can't see my character in one level]) which is a natural thing for a game jam game, but it made an already hard game even harder.
All of that being said, I really think you did an impressive job here, and that given a day or two more these problems could be addressed in interesting ways! Good luck (: