Because the game doesn't support multiple save points, I need to make a backup of my progress so my partner can play too.
I've found the save data in C:\Program Files (x86)\Steam\userdata\XXXX\8870\remote\savedata but making a copy, and later restoring it, doesn't work. I've lost all my progress! I have disabled Steam cloud support in the in-game options, but my original save game is never recognized and I can only start a new game.
Best Answer
You have to disable Steam Cloud support in the game, and also in Steam.
After you have finished playing, exit from Steam and cut/paste the C:\Program Files (x86)\Steam\userdata\XXXX\8870\ folder somewhere safe. Copy/paste it back when you want to restore that particular save.