I really love this sort of aesthetic, both graphically and in terms of the general premise.
I managed to figure out a lot by myself, but eventually got stuck and realised the itch page has instructions haha.
The game would probably flow better if it was easier to park the balloon and you didn't have to respawn so often. I suspect the grapple might also feel better if you had more air movement to give you some nice swings.
Overall really solid entry, I will definitely remember this one in the future as an inspiration :P