
Simply go to https://www.epicgames.com/store/en-US/p/sunless-sea , log into epic and add the game to your cart, it will have 100% off and you will own it forever (well as long as epic is around and allows it).
The game itself may not be for everyone, but is a pretty small download and install, not to mention free! So you may as well give it a try and see how it feels.
Their are two main gameplay states that you will spend around 40% of your time in each. The first is the the overworld sailing, where you navigate your ship , trying to get to your next goal, while avoiding having to eat your first mate or begging a Cthulhu stand in for aid. Food and fuel drain steadily, you can slow this by heaving less crew to eat food, turning off lights to conserve fuel and some events and upgrades. Of course getting a better ship helps too.
You will also frequently encounter hostile enemies on the seas, whom you will have to fight or flee with the appropriately awkward combat controls. Your sailing a crappy steamship, with a bunch of guys you hired out of a random bar and the game makes it feel that way.
While sailing you will often encounter events, which lead to the other major half of the game. It’s a sort of choose your own adventure, with a tonne to read through. It can be a bit nonsensical at times, but the developers have put a lot of thought into making it feel like a connected world, so most things do start making sense when you finally learn and understand a specific bit of world building. There is a lot of dissonance between what the player knows and what your character knows, which can ruin the immersions for those who like roleplay, but that is another major part of the game. Learning through trial and error, as when your captain dies you restart the game, keeping some heirlooms and/or skills from your previous playthrough.

The main plot is that you have just gotten your own ship and have enough savings to start a crew and begin working on a life goal (exploration, writing a journal, amassing wealth etc..), you begin by visiting ports, writing a report and selling the report to capitals harbourmaster. As you do that you will come across events, potential passengers, grand mysteries about the postal service, a rodent based civil war, smuggling boxes of light, maybe sell a soul or 3 (not your own of course… unless your desperate).
The world and stories are fairly unique and engaging, your choices matter greatly, but the game has one major downside. It’s repetitive, not only are you literally starting over upon death, but most stories require you to return at a later date, port descriptions don’t change some already completed stories don’t get removed from the menu, meaning u accidently do them twice and it’s difficulty to memorize what you’ve already done, what you need to do again and what is a waste of time, unless you writing a journal tracking all the storylines and plot points.
Anyway I recommend you give it a go if u like lore heavy RPGs and don’t mind reading.