Thank you very much for your comment and for testing our game! We're stoked you liked it :)
As for the sound design, there's not really a secret haha. I use Audacity to do all of my mixing (as I never got the hang of the other more powerful tools like reaper and stuff). I mostly take some time finding good quality audio files that I overlap together to create a rich atmosphere. For the Mother's TV sound, I looked for horror movies without copyright and I found this 1950s movie called The Wasp Woman (from which the story funnily enough kinda matches the Mother) and I grabbed two 15 minute sequences that I overlapped together to create this sort of intelligible yet uncanny cacophony that would loop on the TV. In addition to that, I added some nice creaking noises to the house to make it feel alive. As for the sound spatialization, it can be done in Fmod (although I didn't use fmod for this project, just good'ol unity audiosources) but I would recommend looking for already spatialized two channel sounds asduring a short game jam time is the most valuable asset. I really feel like having good sound design can really elevate the experience and turn an OK game into a good game or even a great game in some scenarios.
Did you manage to build the boat? I've been thinking about it lately and I think that maybe 4 parts it's a little bit too much and makes the experience longer than needed. 3 boat parts might be the sweet spot.