It's not that underrated but SOMA blew my mind, the story really makes you think and it makes you question the nature of consciousness. A little more underrated is Ghost Trick, it's a VN but it has a lot of puzzles, it has a great story and fun puzzles. Something super underrated is The Legendary Starfy on the DS, played it as a kid and recently back and I loved it, the levels are great and super creative.