When I played through Blue Prince, I had an important area of the game undiscovered for in game weeks because I just didn't notice a path that was not meant to be hidden. It was in an area that it made no sense for me to further explore because it was challenging to get to and seemed to have nothing else to offer (I presumed until I had unlocked something further in the game). It was a big relief when I was talking through my progress with a friend who was further along than I, and they prompted me to go back and look again.