Purged saves on repeated occasions.
I'm not sure if this is a problem with the game or the steam cloud itself, but I've gotten a 'Files could not be synced' error two times now after trying to start up the game, and both times all my saves were deleted. In their place empty slots. The first time it happened I didn't mind it much, figured it was just a one-time error. I couldn't be bothered to check it up online because the saves I had were pretty useless anyway. But last week I finally managed to go beyond the 15-star system mark, a new record for me. Unfortunately the saves are gone now. And I don't want this happening in the future again. I'd rather not disable the steam cloud as I switch between computers a lot. But if there's no other solution, I guess I'll have to.