Sunless Sea is a rogue-like aquatic exploration game wherein you make decisions regarding who joins your crew, how to upgrade your ship, and where to navigate to, and what activities to partake in while docked. Think of it almost like a choose your own adventure but in game format. The game itself takes place within the universe of Fallen London which can be explored in Failbetter Games project here on Story Nexus (it's free by the way!). That project was also similar to a choose your own adventure or interactive story if you will. Sunless Sea is said to include Lovecraftian themes which is usually a plus for any horror game! Do yourself a favor and pick this one up soon. There was also mention of DLC coming in the future, but I'm not sure if that is by way of free updates or paid DLC. You can purchase Sunless Sea by clicking any of the links below. If you have played Fallen London or Sunless Sea and care to share your thoughts please let me know down in the comments!
Failbetter Games Official Site (via Humble Bundle)
Good Old Games a.k.a GOG.com