Sinking Eternity
This game is a single player game. It reminds me of Subnarnica but with different things. You pretty much wake up from a really deep sleep and end up having to live off the ocean. It is a crafting game with beautiful graphics. You also have to watch your oxygen or you could die but don’t worry there are blue coral under the ocean to supply to air. The demo was short so there is not much I can write but watch the game play to see.
Get it here (not affiliated with the devs)