Sunless Sea is an awesome game, I highly recommend it! There is a lot to explore and every time you play will be something new.. Don't be discouraged if you die right away, it is very much like you learn a bit more in every life. It is harsh, there is no tutorial. You start the game with a little book full of some info on various things, but when it comes to survival, you have to learn on your own. Don't be afraid to take risks, when you die you don't lose everything and once you get a good feel for the map, it gets much easier.
tl;dr : You sould play it if you are not afraid to take risks.