I just bought the game and included the Artbook and Soundtrack items as well. I went to the Download Page and saw the game Installer files, the Artbook file and the Soundtrack files were all listed. When I went to the GOG Downloader Links page the only "goody" added to the downloader was for the Artbook, the Soundtrack files were not added. I will of course try a "save as" action on the files (after the other downloads are completed) but thought I'd let GOG Devs know about my experience.