Darkest Dungeon

Ruin has come to our family.

Darkest Dungeon is a 2016 Roguelike/Dungeon Crawling video game in which the player takes on the role of an heir to a once-proud but now-fallen noble house. The heir is summoned to the old estate by a letter from his ancestor, which explains that he heard rumors of great power dwelling beneath the manor, spent the family fortune excavating it, and unearthed terrible things. The player then recruits, equips, and dispatches teams of heroes into various dungeons surrounding the manor to put down the monsters that have come to dwell there, and clean up the Ancestor's mess.

Tropes used in Darkest Dungeon include:

Ascended Meme: Wayne June (the voice of the narrator/Ancestor) recorded a set of Darkest Dungeon-themed voice notifications for Twitch streamers. It includes some Shout-Outs to Undertale, Dark Souls, and "Truly, this is the Dankest Dungeon."
Announcer Chatter: The Ancestor provides commentary on battles, encounters, and town events, but he doesn't really "chatter"; he makes ominous, portentous comments about victory and/or doom.
Arc Symbol: The "Stress" symbol (which is, incidentally, an "arc symbol" with lines through it, resembling a thorny halo) begins to figure more and more prominently on enemy attire and the architecture as the heroes plumb greater depths of the dungeons.
Army of Thieves and Whores: The brigands which inhabit the Weald are such an army, and the player's roster of heroes may not be much better.
Body Horror: Many of the enemies (especially the swinefolk) are quite horrific. The Ancestor and Heart of Darkness can also inflict Body Horror on the heroes as an attack.

Ancestor: "The flesh is fluid, it could be changed, reshaped, remade!"

Book Ends: "Ruin has come to our family."
Cosmic Horror Story: Creepy ancient manor? Check. Eccentric ancestor unleashed horrible eldritch things from beneath it? Check. The end of the world is inevitable, if not now, then some generations later? Check.
Go Mad from the Revelation: Several enemies (Madmen and the Prophet and perhaps the Ancestor) already have, and as stress mounts, the heroes run the risk of following them. Some enemy attacks explicitly revolve around revealing unsettling things to the heroes to increase their stress and provoke their fall into madness. In the ending, the Ancestor implies that the Heir is next.
Idiosyncratic Difficulty Levels: Dungeons are labeled as Apprentice (balanced for heroes of resolve level 0-2), Veteran (2-4), Champion (4-6), and Darkest (challenging even for 6's).
Luck-Based Mission: Dungeon layouts are randomized, and while they have "Apprentice", "Veteran", and "Champion" designations, there is still a wide variation of difficulties within each, and party and trinket choices add even more variables to the pot.
New Game+: After beating the game, the player has the option of starting saves in NG+ mode, which makes the enemies tougher, locks the difficulty options to maximum, and places a timer and death limit before the Heart of Darkness wakes up and the player loses.
Random Number God: Hitting, critting, dodging, blighting, bleeding, debuffing, stressing, and in some cases healing are all based on rolls of the dice. The player can upgrade hero equipment and skills, and use trinkets or certain supplies to improve their odds, but rarely is any action truly certain to succeed.
Sanity Meter: Each hero has a stress meter. Enemy critical strikes, certain attacks or unsettling curio encounters increase it, and player critical strikes and some player abilities reduce it (as does spending time at the Tavern or Abbey). There's no Interface Screwing as the stress mounts, since it's not really tracking sanity per se, but when it reaches 100, the hero is "tested" and will obtain a virtue (e.g. "Stalwart") or affliction (e.g. "Abusive") until their stress is reduced. If the hero becomes afflicted, their stress can mount higher still, until reaching 200, when the hero suffers a heart attack and risks dying. (A Virtuous hero cannot increase above 100 stress, though the effect only lasts for the duration of the expedition.)
Schmuck Bait: Many curios are more troublesome than they are worth, such as books and corpses (unless the proper item is used -- though even if the player knows this, heroes with certain quirks have a probability of touching them anyway), but a few are downright cheeky, such as the Shambler's Altar. "Place a torch if you crave the void!" Suuuuure. The torch gets dropped to zero, and the heroes get sent into the "outer spheres" and fight the Shambler.
- Likewise, the "Bandit's Trapped Chest" in the tutorial: "Something is not quite right with this one..." Enjoy your blight if you have the hero touch it.
- And in the New Game+ tutorial, the "Transcendent Terror": "Surely nothing good can come of a dialogue with the dead...?" +100 stress and an affliction for the rest of the dungeon -- and the next dungeon as well, since no stress-relief activities are unlocked yet. Sometimes jokingly stated by fans as "Talk to the ghost in the tutorial to get your NG+ bonus!" for extra schmuck-baiting.
Sesquipedalian Loquaciousness: The Ancestor has a pretty severe case of it, sometimes. "Monstrous size has no intrinsic merit, unless inordinate exsanguination be considered a virtue."
Shout-Out: The default name of the Occultist is "Alhazred", named for the author of the Necronomicon in the Cthulhu Mythos.
Unwinnable: Averted (outside of NG+) -- no matter how many heroes die, there will always be more, and while it costs money to upgrade them, they will join your roster for free. As the game says, "Heroes are a renewable resource."
Xanatos Gambit: If you hadn't answered the Ancestor's summons, the Heart would have escaped in the future when the stars were right, and because you did answer, the resulting bloodshed and chaos have accelerated its awakening.