Well, in my case I had looked it up on https://howlongtobeat.com which said about 2 hours to win the game and 4 hours to complete it entirely, so I think that might have affected just all I did in the game? Like, I might have explored more if I hadn't expected it to be so short. Even so, it WAS a surprise when I suddenly found myself on the peak, as that felt like it came pretty quick.