When I first enter the game, the save function doesn't work at all. All save slots are empty, no autosave, cannot manually save the game either.

Then I go to the game folder, use the winsetup.exe, check "Custom game saves path" (which redirects the save path to steam library by default). Then I reenter the game, and the save function works fine this time.

I presume this bug was caused by my system user's name containing Chinese characters. Hope the dev can fix this. If my assumption is right, this bug can affect many players in Asia.