itch.io

Great Question! I've actually been thinking about the best way implement this. The web saves work in a very similar way to the Steam version, In theory, I should be able to create a button on the web version to download your save to import into Steam. 

The only question is how seamless I can make the transfer. At it's worst it'll be download a file -> manually place it in a folder, I think...

This is now implemented in the settings tab, Export will download a save file, import will let you select that file to import into your save. So I can confidently answer "Yes" now :)