I am the type of person that typically does lots of research before purchasing a game. That being said, my suggestion to you is: do NOT watch any let's plays or dig too deep into the literature on this game. Just do yourself a favor and play Subnautica first. The thrill of discovery is so central to the initial playthrough. With minimal hand-holding, a beautiful, exciting (sometimes frightening) atmosphere and a refreshing return to gameplay-driven narrative, Subnautica is sure to stick with you long after your introduction to the aquatic world.