Darkest Dungeon is a game that's based entirely on RNG, and is designed to be difficult, even frustrating. Characters will die, you will get unlucky, yet you still must clear the Darkest Dungeon.
Pro A nice challenge with plenty of depth
For players that lean more towards a challenging, satisfying experience akin to something like Dark Souls, Darkest Dungeon doesn't compromise on difficulty. The game seeks to make each victory a satisfying experience, and on that front it largely succeeds.
Although the game lacks much depth in regards to armor or weapons (all Crusaders will use the same weapons and armor, all Lepers use the same weapons and armor, etc), characters can differentiate themselves thanks to their own personal quirks, their exact skillset and their trinkets carried, all of which is further amplified by the concrete class composition of each individual squad.
The game will force you to experiment with squad compositions due to various afflictions preventing you from running the same squad endlessly, but this acts as a strength, since finding a good squad composition can be a rather pleasing experience.
A good choice for players that enjoy strategy turn-based games, as well as those who appreciate the RNG-aspects of rogue-like games or simply want a nice challenge where unlocking certain Steam achievements truly feels like an accomplishment to be proud of.
Pro Excellent presentation, narration and music
It can be difficult to describe at times to people that haven't experienced a game, but little things like the overall presentation can really add to the experience. In the case of Darkest Dungeon, the narration lines are simply expertly delivered, and hearing the narrator react to the events of a battle really adds to the excitement and how engrossed you are with it all. A great soundtrack definitely helps too, and Darkest Dungeon has that in spades. I realize fully that most people who've never played the game won't understand how "excellent narration" could be a major point worth praising, but trust me, you won't be disappointed and you'll find yourself surprised how much something so simple can add to the experience. It's just a finely polished presentation that helps the player feel immersed.
Even more basic things such as the lines spouted by the various characters really add to the experience. Whether it's the Jester breaking out into hysterical laughter after landing a crit, the Leper emotionlessly voicing a brief line that seems to reflect his world philosophy after downing a giant enemy ("Summer before Fall," "Petals must fall"), or the Bounty Hunter only remarking with a brief "Hmph" or a snort after effortlessly defeating a boss, the character's personalities are simple, yet surprisingly interesting. This adds to the experience and makes you care about some more than others, though you may want to be careful about growing TOO fond of any of them, since odds of survival are rather slim...
Pro Immersive atmosphere
Darkest Dungeon has an almost intoxicating atmosphere created by three main aspects.
Firstly, it’s the visuals: the somber color palette that accompanies a sunset, the creepy environments your party of four will anxiously proceed through, and the detailed, fearsome, and sometimes disgusting enemies that will tirelessly try to slaughter you.
Secondly, the audio: an eerie soundtrack filled with murmurs of otherworldly creatures, teemed with bloodcurdling sound effects that render monster strikes more impactful. Even a charismatic narrator providing insightful interjections, as uttered by his mysterious, deep voice.
Lastly, it’s the highly unpredictable and sometimes unfair gameplay. Whatever short triumph you may have, it will get drowned in a sea of despair.
These elements combined make it very easy to immerse yourself into the world of Darkest Dungeon.
Pro Great monster design
There's a wide variety of extremely well-designed monsters and characters in the game. You confront bandits, skeletons, fish men, pig monsters, and all sorts of Eldritch horrors.
But what's really noteworthy though is the boss monsters design. Both the art style and abilities are unique and hard to find in other games. For example, there's a boss which is pretty much a lump of flesh that can transform into a Siren and even seduce one of your allies to its side temporarily.
Pro Has some outstanding narration that adds a lot to the great atmosphere and backstory of the game
The voice actor who does the narration is excellent. He portrays an ancestor of the player character who first discovered the dungeons you are exploring but then lost his mind from what he discovered in there. This tiny bit of backstory does a lot to add to the overall Lovecraftian feel of the game.
Before fighting a boss monster, the narrator will jump in to explain the backstory of that monster and the role it played in the maddening quest of the character's ancestor himself.
Pro The gameplay constantly keeps you on the edge
The rampant and merciless randomness built into the gameplay always manages to keep the player on the edge. Even the turns in which characters are allowed to do their actions is decided randomly behind the scenes.
For example, you might be planning to heal one of your characters with your healer next turn, but you can never be quite sure whether you'll be able to or whether the enemy will deal the killing blow
Pro Outstanding narration
Even though the only character that talks in this game is the narrator, his delivery of the lines is excellent. He talks in a deep and raspy voice that is also very pleasing to listen to.
The narrator usually describes the events happening on-screen such as upgrading your settlement buildings, recruiting adventurers, various dungeon interactions, and many more. Additionally, he’ll start dropping story bits every time you near a boss, creating a very minimalist approach to storytelling that is also very enjoyable.
Pro Great monster visual design
There's a wide variety of extremely well-designed monsters and characters in the game. You confront bandits, skeletons, undersea terrors, pig monsters, and all sorts of otherworldly horrors. There's a lot of gruesome detail on each and every enemy, so the longer you'll keep looking the more you'll notice. This can be bloodstains, an extra set of eyes, an appendage that looks like a tentacle, and many more. It sometimes really feels like you're losing your mind alongside the adventurers, seeing whatever fits into your schema.
Pro Interesting adventurer management
While the fabled heroes are off slaying dragons, battling demon kings, and saving princesses, the small-time adventurers have to clean up the dregs. You as the lord of a small settlement will employ these adventurers to clear out the mysterious dungeons surrounding your property.
To clear a dungeon you’ll need to prepare adequately. This involves having decent party setup, which usually consists of at least 1 tank, 1 healer, and 2 damage dealers. This also includes having enough provisions such as torches and food. Planning out what and/or who to take with you can sometimes take as long as running a dungeon but it really makes you feel like you’re organizing an adventure.
Another interesting part is the stress mechanic, causing your adventurers to accrue stress as they keep adventuring. If stress passes the first threshold, your adventurer might incur various penalties or even refuse your orders. If stress passes the second threshold your adventurer will die from a heart attack, so it’s important to relieve it regularly. This can be done by sending them to the tavern to blow off some steam or to the abbey to request absolution. Either option will make them unavailable for a week, so it’s a good idea plan ahead and have multiple parties of adventurers ready. This mechanic makes it feel like you’re managing real people rather than the indomitable figures often seen in fairy tales.
Con Potentially tedious
Darkest Dungeon will likely demand you level multiple characters up for a very similar experience being repeated. Part of the interest in the game is experimenting with different squad compositions and seeing what works, however, the game needlessly worsens this effect by limiting where certain heroes can go.
For example, the first bosses you encounter in the game can only be beaten by level 2 heroes or lower; the moment a hero hits level 3, they'll refuse to bother. Given that there's 8 bosses below level 3, this means you can basically expect to need to make 4-8 squads just to beat them all since 1-2 victories may level the squad too high to fight the rest.
Those same 8 bosses need to be fought again at levels 3-4 and then at 5+. After that, the Darkest Dungeon - the final series of dungeons - can never be revisited by any characters that succeed. For example if a squad beats the first level of the Darkest Dungeon, they cannot be used again on the second, third or fourth levels.
This limitation can feel rather aggravating, especially towards the start of the game with the below-level-3 bosses since your character roster size is fairly limited, so simply juggling space to fight all bosses is a challenge in and on itself. Luckily it does get better beyond that, but this very mechanic is likely to scare off newer players who quickly tire of that needless limitation.
For some players, Darkest Dungeon might feel a bit repetitive and tedious, and these rules only make the experience that much more grueling. On that same note, most character improvements are initially very expensive and downright un-affordable. The solution? Throw enough characters at the dungeon that you finally earn enough artifacts to lower the costs, then future squads of characters will be able to succeed where past ones failed thanks to sheer cost. Grinding is sadly a part of the experience. The repetitiveness shouldn't be too bad for anyone that likes games akin to Binding of Isaac for example (same run, same gameplay style, but different enemies and loadouts each time to keep things fresh), but could potentially wear on some player's patience after a time.
Con It can be frustrating at times
Darkest Dungeon heavily relies on random events that can happen at any point in a dungeon. Some of them don't make any sense and most of them don't feel fair.
For example, right after stepping inside a dungeon your characters might suddenly go hungry. If you don't feed them they'll get a penalty, setting you back for the rest of the dungeon. If you feed them you'll have used up your food but your characters might still go hungry again.
You can't reliably plan around stuff like this, which can be annoying.
Con Gets really repetitive
You'll spend dozens of hours repeatedly running the same dungeon, killing the same enemies, and collecting the same loot just to progress further into the game. On top of that, if you lose a character at any point, you'll be set back by another 3 hours. If you don't enjoy grinding, Darkest Dungeon might not be the game for you.