After having seen this game being streamed on the GOGcom twitch channel (thanks again, DarkSaber2k), I decided to get it and, boy!, is it great!
It's not easy, when you're doing a horror game, to strike that balance between exploration, puzzles and gunplay, all the while keeping the player weirded out and spooked. It's easy to just rely on jumpscares, even when you do have a good horror game in your hands, some studios will still include the occasional jumpscare just to keep things... "lively" (I don't even loathe jumpscares, but I do think it's a lazy mechanic that tends to be overused in horror games and movies), and In Sound Mind has no jumpscares whatsoever. Some times you'll get startled by stuff that some people would consider a semi-jumpscare, but it's never a full-on thing, and they're always used to startle the player, not "scare" us via a loud sound accompanied by something suddenly being in our face.
The game deals with some subject matter that some might find offensive, namely mental health issues, abuse, violence and anxiety. It's a psychological thriller, so... this should go without saying, I like to assume that if people buy a horror game are aware of the topics these games can address.
Really nice to see this on GOG, if you care about well-made horror games, I recommend you to get this, because it hardly gets any better than In Sound Mind (also, the game is made using Unity, so it'll probably run on your machine, even if you're not sporting the latest and greatest in PC hardware -- just make sure to turn some of those bells and whistles down).