I have been wondering why this part of the soundtrack was not officially released (available only in-game)...
This custom mix was made from ripped game soundtrack files, all credit goes to Grotto and Niilo Takalainen.
The second part is an absolute banger, I get shivers whenever I hear it ingame (in the Hiisi base level)!
Many thanks to Nolla Games as well.
Image -
Music - Grotto & Niilo Takalainen