I have resently tried to restore GalCiv2 from a backup made using SDC. At the first attempt I got only the game files, but not tutorials, sound and video. Then I renamed the .sdc-file to .zip and tried again, this time the whole game was extracted, including sound, video and tutorials. But when I played the game there were no sound, no video, and no tutorials, furthermore I was not able to redownload those elements with SDC without first uninstaling the whole game, so I ended up uninstalling and letting SDC download the game with all sontent. Luckely I don't pay for trafic on my internet connection.
I submitted a bug-report on March the 14th but have not heard from SD since.
