I tried to complete this game on three different occasions, playing it on Steam and Epic.

Run 1: First look.
This could have been one of the best roguelike RPGs out there, but they destroyed the game by failing at one key point: Balance. They gave the enemies a spiked sledgehammer that shoots lightning, fire, and ice, and asked you to fight them with a broken spoon while poisoned, cursed, low HP, and death is permanent because "let's add some artificial difficulty, this is a serious game", which could be nice if this was an action-focused game where you could dodge and chip away at the enemy, but it's a turn-based RPG, and the enemy will hit you no matter what. And they do hit you, a lot. The only thing this game has going for it is the art and the actual Darkest Dungeon, which I'll never reach without spending 100 hours grinding and hoping for a lucky run. Fuck this game.

Run 2: Copium.
Attempting to complete this again was a mistake. I only got very frustrated for nothing, wishing this was a better game, I want this game to be good, but it just isn't fun, it's just a huge tag bait.
People pretend that this is a good game because "it's difficult" and looks very Lovecraftian, but the game itself sucks. The developers are just some random edgelords that hired a good artist, and good for them, the game looks awesome, but that doesn't make a good game.
I also found that if you get on the Steam files, you can edit the game and balance it yourself, but why would I do that? That's their job as developers, and it would take hours to learn how to understand the code and hours to edit the files without breaking the game.
I gave it another try. This time I spoiled myself with some guides, hoping to complete this game within reasonable times. Huge mistake. I still can't put my finger on what's so wrong with this game other than balance, but I think it's fundamentally broken.

Run 3: I can fix it.
I should have stopped on run 2, but I couldn't. Months passed, and I learned how to edit the game files to balance it myself.
I made healing work overall, lowered debuff chances and/or effects (for both sides), fixed how the Stress meter works, changed a lot of skills to either be relevant or at least usable instead of having a character just to spam 1 skill and nothing else, and added proper item stacking amounts, stacking items on such low numbers with a very limited inventory space is just stupid. I also buffed certain aspects of the enemies, resistances, abilities, frecuency, rarity, and overall stats. I added balanced buffs for the enemies and debuffs for the player. There are many garbage enemies that I made relevant and entertaining to fight against. I spent weeks getting down to the details of each single aspect of this game to fix it. And at the end, I got a very well-balanced game, it's still hard as fuck, but now it's playable, and the combat is enjoyable instead of complete torture. You'll still get sick, still die, still get debuffs that hinder your characters, and still get random encounters against unfair enemies, but now you can plan ahead and fight back instead of playing a dice game with your time.
After removing the dozens of hours spent editing files, I spent over 30 hours playing to "complete" the game from start to finish. And I say "complete" because there are 120 impossible achievements that are as unbalanced as the base game, for example: "Have a character survive 5 attacks at Death's Door in a single combat", Death's Door, for those who don't know, is when your character reaches 0 HP but is still alive, and every hit can and will most probably kill them forever, just thinking about the chances gives triggers PTSD attacks. Adding to that, even if you are the luckiest man alive and manage to get all the achievements from the base game, there are many achievements locked behind a paywall, so you'll never complete the game unless you pay them even more money after they tortured you with the bait of a great game and gave you the worst roguelike RPG that the world has ever seen.

After all that nonsense, I started to look at the game in a different way. I completed the Darkest Dungeon, and there was nothing else to do. The game just ends very unceremoniously, and allows you to keep playing for no reason, as if there was something else to do. The last boss wasn't even that good, it was more unfair, unbalanced, torturing shit, it was not worth it at all.

So there is no story, no exploration, no mystery to uncover, no endgame, not even coop to have fun with your friends or any other online interaction, and no feeling of completion as the achievements exist but are literally impossible to get unlses you cheat your way to each one of them, probably spending over 200 more hours to get them all. And then it hits, the game is just empty, it's a souless turn-based combat simulator that baits you with good art and false promises.

This game is 100% about combat efficiency, anything else outside of that is irrelevant. This is about how good can you plan ahead and adapt your party to the situation. But they failed at creating balanced encounters, balanced enemies, and worst of all, balanced characters, they failed at the one thing this game is all about, which makes it one of the worst roguelike RPGs that I have ever played, if not the absolute worst.

But there was something charming about it, one thing that the developers did not intend: This game is like buying a broken car just to fix it. I managed to do it, and it felt good after reaching a good balance, I had a lot more fun balancing the game than playing it.