Thanks for the feedback, happy to hear you liked it.
I'll keep that in mind about the checkpoints, I figured it might be short enough to not need them but I suppose the spike obstacles can be a bit tricky. The hitboxes are the exact character/object sprites I could make them a bit smaller.
The rock enemies don't have code to be able to kill the player lol, I definitely not intended if they managed to kill you. The deflation momentum is based on the last direction you pressed if you pressed down it'll just release air upwards, and yeah the directional input is intended for hurting the boss. I suppose the case you can use the deflation momentum to go through them without damaging them is something I've overlooked sorry about that.