I have been playing videogames for over 20 years non stop. This single game alone is simply the best game overall I have played so far and that says a lot.
10/10 story
10/10 gameplay
10/10 atmosphere
10/10 soundtrack
10/10 visuals
I know it's not a triple A game but man, this masterpiece gives you a sense of exploration, terror, mystery and agony that no other game has ever come close to it. Visually, the game is just beautiful, every biome, every plant, every creaure ads to the game's beauty. Even though there is resource gathering, you will never going to feel that you are grinding or making chores for the game. The progression system of the game is genius and keeps you hooked. No stupid quests, no grind, no meaningless chores. The concept of the story is amazing and you are going to want to play the game just to find out what will happen. I also like very much the fact that the game does not guide you at all because it gives you a cool sence of researching, exploration and achievement that every survival game should have. What is more the game handles darkness/visibility perfectly, prepare for some really scary creature encounters in the dark...
The only problem I had playing this game is that now every other survival game i'm going to play ever will probably feel luckluster compared to Subnautica. It creates a whole new level of expectations for future games. Every aspect of this game is pure perfection. Buy it!