This is an awesome game! Just played your prototype, now played this one. I absolutely love the whole concept of moving inside a body to cause certain effects, supported by actual scenes of what's happening. Also, the gameplay fits what you're trying to do, the game elements match with the effect you're trying to achieve in the body.
The music also complements everything really nicely. I can't stop complimenting you, but the puzzle elements also are great. The disappearing platforms caused me a bit of thinking, but nothing too difficult. Also, that map, actually showing you navigating through the body, nice addition! And to top it off, the controls are really tight.
I am genuinely impressed by the originality and quality gameplay!
Oh, and from a developing perspective, also like that your prototype exactly is what it is, a prototype. The final game is really a continuation and (huge) improvement of that prototype, exactly the purpose of course, but still, nice achievement I'd say.
Takes me back to the cartoon series of my childhood a bit that was called (it was French originally): "Il était une fois... la Vie". You should Google it, it might give you some ideas if you want to extend on this concept further.
<< some spoilers below >>
I'm now in part 3, steadying the hands and I love how the whole atmosphere of the level changed (spikes gone, no alerts anymore, relaxing music) when I relaxed the first hand.
What I meant above is that I like that your mission is to focus the breathing (with an awesome puzzle!) and after you've done that, you actually use 'air platforms' to move around the level.