Darkest Dungeon is dope as heck. One of the few games I bought in Early Access; wasn't disappointed with it at all, and it's been improving a ton through the year or so.
It's a game about delving through dungeons with a party of 4 characters, and getting into turn based battles where character positions matter a lot. You not only suffer damage in battle and exploration, but also stress and must manage it as best you can. Individual characters will permanently die, but you can recruit a large roster so your game is not over simply because your party is wiped.
The eventual goal is to gain enough levels and items for a party to be able to brave the darkest dungeon itself!
Here's a LetsPlay video from BaerTaffy playing the tutorial + a first mission from it's initial release... the mechanics are mostly the same, so it's still a pretty good showing of what the game is all about.
https://www.youtube.com/watch?v=OF1uhwxh8tk