Cool stuff!
I thought that the dynamic between how much oxygen you have and how difficult it is to traverse the stages was pretty interesting, though some narrow corridors/turns sometimes make you wait quite a while to actually progress the stage because of it.
Going through some of the dead ends also means an instant restart if you take their path all the way, even if you use the oxygen provided in that path. This kinda made the dead ends functionally useless and feel unfair, since you don't really gain anything aside from "don't go there next time."
The dashing mechanic is also fairly weak, since using it consumes more energy per distance than if you had just moved normally. It's also difficult to see what's ahead of you if you do use it, and it led to me popping the balloon on spikes I didn't see.
That aside, I did have fun playing through the stages. Keep making awesome stuff.