Since in this game the music is essential to actually solving the puzzles and since the GOG release does not include it as an extra (neither does it contain the manual), here are the places, where you can download these necessary/fun materials.

1. OST, in-game sounds (for download and for online listening):https://downloads.khinsider.com/game-soundtracks/album/shivers-2-harvest-of-souls-pc
2. OST streaming only: http://www.sierrahelp.com/Music/Shivers2Soundtrack.html
3. Manual: http://www.sierrahelp.com/Music/Shivers2Soundtrack.html or
http://www.replacementdocs.com/download.php?view.806
4. Excellent hint system to the game: http://www.uhs-hints.com/uhsweb/shivers2.php

Enjoy!

PS.: I hope I'm not violating any forum rules with this (and the music is indeed not some fancy extra, but an integral part of the game) and once GOG creates a Harvest of Souls forum (it does not exist presently) this topic should be moved there.

First off, thanks for all this.

As for it being moved: Gog usually groups games of the same series in one subforum, so this will likely be the subforum for both games.

awesome! thank ye

I just bought it, and I was surprised the music was not available as extra downloads !

Thank you for righting this big wrong - and happy Halloween !