At first, I didn't think Darkest Dungeon was for me; It's way too oppressive and difficult, and the game wears that on its sleeve. I struggled a lot at the beginning, experiencing full party wipes with characters that I had already started to become attached to. Then I did something I almost never do; I installed a few mods. This simple tweak made the game much more palatable for me and I managed to get through a huge chunk of its content. Darkest Dungeon is a fantastic title and I wish I could've played the whole thing.
After selecting a difficulty, the game throws you in a tutorial of sorts where you walk through a simple dungeon and fight a few introductory battles. I feel like movement is weird in Darkest Dungeon, you click or press certain keys to move forward or backward and it's strangely imprecise. Sometimes you move just a little bit too far and need to backtrack in order to click on something. I wish movement was more rigid or tile-based. I immediately turned all difficulty settings down, because I wanted a fair chance with the game and that felt like the thing to do.
Characters in Darkest Dungeon come in waves between each mission and you can recruit them. They all have a bunch of things, quirks (both positive and negative), stats, gear and skills. One of the mods I installed was to remove negative effects from accessories. In the base game, all accessories were somewhat risk/reward based, you could get +5% critical hit chance, but -5 HP, for instance, or +10% blight resistance at the cost of -10% bleed resistance. Removing these negative effects made them better while not breaking the game. Quirks can range from simple stat boosts to specific afflictions; like characters that will steal items or refuse to act in certain situations.
Combat is really satisfying when it goes your way. You have a party of four characters with four moves each and each move has its own range (where you need to stand and where you can hit with it) and effects, so it's really fun to try and create the good party that will survive and dispatch enemies with ease. Your characters have health and stress levels; If health goes to 0, you are at "Death's Door" and you can take a few hits but risk dying with each one you take. If stress goes to 100, your character will develop a really bad ailment (or it can be a good one, but that happened very rarely), and at 200 stress, they die of a heart attack. My first runs through the game were nightmares and my characters died left and right, high stress from difficult encounters compounded the difficulty and I wiped entirely once.
Afterwards, I played it extremely safe (because I chose the game mode that allowed that). I slowly accumulated relics, gold and accessories from completing missions and moved through the ranks of battles, upgrading my town along the way. The town is full of interesting buildings that you can upgrade, to get more characters, to improve their gear and skills, to cure their quirks and get rid of their stress. Before leaving for each mission, you need to buy some torches and food in order to manage light and hunger levels. High light improves your chance to surprise enemies and while low light gives more critical chance to both sides (and better loot), it also increases stress, so I always tried to run my torch at maximum.
There are plenty of cool systems in Darkest Dungeons, while exploring you can interact with objects that either give you treasures or negative ailments (and I kinda wish the game would track what does what, because I had to read a FAQ while playing in order to never trigger the objects that always ended in drama) you can take longer rests when you are on longer missions and use camping skills, there are a lot of bosses to defeat and plenty of classes to pick through for your perfect party; Although you can't get too attached to them because you'll need to cycle them out in order to reduce their stress.
I really liked Darkest Dungeon. It's not the kind of game you can just play while doing something else, and it can get very stressful (especially if you think the game is manageable but suddenly things turn for the dire) but it's an incredibly solid RPG with plenty of customization and upgrades. After a few small tweaks, I really enjoyed it!