Viewing post in The Curse Of Something comments
I do have an idea, (But this idea could be what you already do or have tried) but perhaps you could do what Trials in Tainted Space does regarding save files, saving like usual, but also let you save your data to a file then load the file back up?
That way, all you really need to do is make a designated save file in a file format and let you download it?
I noticed that Dawn of Corruption does the same thing if desktop site is on, the save menu is very similar between Curse of something and Dawn of Corruption, but that's on a website/Pc version. However that does make the idea feasible.