What a seriously cool game! It's neat how so many things are interactive, but it'd probably be a good idea to provide some indicator for what is and isn't interactive (like maybe interactable things are a different colour or pulsate). I also had difficulty figuring out what to do at the start. I know that there was a tutorial page at the start, and looking back at it, the tutorial is clear as day, but I have a horrible habit of skipping past instructions. It'd be nice if you could perhaps pause the game and it'd show you those controls again?
The final critique I have is regarding the limited number of patches that you have to repair your balloon. I agree that there should be some limit on how many patches you can do, but I frequently lost track of the number of patches I'd used, then go to use another and find I have none left. I believe the issue is that the remaining patches are shown at the top right, whilst all the other action is going on in the centre of the screen. Celeste (the game) does a great job at avoiding this by representing the availability of dashes through the player's hair colour. Perhaps you could have had the patches dangle off the edge of the balloon, so that each time you used one, you could clearly see how many remain without looking at the indicator at the top right.
This game is really great tho, and I wish it was longer. It was an interesting movement scheme, paired with fun ineractable environment pieces and frequent new challenges. I simply adore the density of new obstacles, each challenge feels new and every new checkpoint felt fresh. Brilliant design capped it off for an all round amazing game.