I suggest you try this after finishing the game at least once or after watching the optimal route on YouTube.
Basically you just have to play ideally and quit to main menu after each perfectly executed segment of the game (you can literally just make one good move). Then you want to backup your save data from ...\Steam\userdata\<UserID>\817510\remote. Once this done, continue the game and quit again after several succesful shots to backup your progress. If you fail - quit to menu and use the file you've backed up earlier.

Here's my save data nearly at the finishing line (2-3 flying islands remaining, i know you can do this) in case you'd rather pass the 1st method:
https://disk.yandex.ru/d/wZI6fXCCvesu-Q