It's pretty cool how you managed to make me stress with just walking! I managed to leave the moon, so I'm happy :D
What's weird is that the first bottle of oxygen is the hardest to grab, then it becomes gradually more and more easy as time passed, to the point where I optimized time by grabbing all my bottles at the last second. The golden pad and the rocket arriving where good elements that added some stress back and made the end of the game tense, which is good. Maybe you should make sure that not too many bottles are in the world at the same time, all the while making sure one is always in reach.
Good job!