The game looks very polished, well done! I like the atmosphere, and the music fits really well into the game. I couldn't quite figure out what was going on with the black things and whether there was some remedy/pattern to how/why they formed, so I didn't get too far into the game, but overall it was very relaxing to play!
Also, the windows version seems to be built in debug mode, was it meant to be like that? If it was built for debug, it does little to no optimization to the game, and I feel like the game could use some optimization since it can be slow sometimes. (mostly taking this info from here: https://docs.godotengine.org/en/stable/development/compiling/introduction_to_the... )