Video Game / Sunless Sea

Explore an underground ocean. Battle sea monsters. Discover strange lands. Go insane. Eat your crew.
Die.

http://static.tvtropes.org/pmwiki/pub/images/743676596ceb49afa2bdd19bd6f87af5.jpg

Sunless Sea is a Role-Playing Game from Failbetter Games, the creators of Fallen London, following a crowdfunding campaign on Kickstarter. Set in the Fallen London universe, the game casts the player as the captain of a steamship, exploring the Unterzee - the colossal, largely uncharted underground lake that surrounds the sunken city. Noted influences include roguelikes with action elements, like FTL: Faster Than Light and Don't Starve; Wide Open Sandbox exploration and trading games like Sid Meier's Pirates!, Elite and Tai-Pan; The Crimson Permanent Assurance; and immrama.

Following a period in Early Access, the game is available through Humble Bundle, GOG.com and Steam. The Zubmariner expansion pack, featuring underwater exploration, was released on 11 October 2016. A sequel, Sunless Skies, is set to come to Kickstarter in February 2017.


This game contains examples of:

  • Abnormal Ammo: The Icarus in Black, which fires extremely angry & suicidal monster hunters. The reason it's actually able to do this at all essentially amounts to "Made in Iron Republic"
  • Adam Smith Hates Your Guts: Mostly averted; the prices of various commodities and essentials varies between ports with reasonable justifications (e.g. London has fair, manageable prices, but provisioners on a distant backwater island charge twice as much for fuel and supplies as elsewhere). Invoked, however, in Khan's Heart: you will be extorted if you don't have a licence to trade in the city's proper market district (though if you managed to get a proper trading license, their price becomes reasonable, and you'll also get access to wider variety of trade goods).
    "The Khanate merchants grin when they see you coming. An unlicensed foreign captain? They'll pick a price and triple it."
    • That said, most of the new Ports in the Zubmariner expansion have really low prices on fuel and supplies, at least when compared to other islands. They're usually only one or two more echos than the London prices, making these ports an excellent source for a long trip.
  • A Foggy Day in London Town: Even in the Neath, London and its surrounds still have their fogs. Their practical effect, if zailed through, is to impede aiming, and to thoroughly spook your crew.
  • The Alcatraz: Wisdom, a prison in the midst of a sea of enormous lily pads, guarded by huge, multi-eyed toads called knot-oracles. To get someone out, you'll need to either pass a ridiculously difficult Veils challenge or pay an exorbitant bribe.
  • Alien Geometries: Neath's geography is...weird. Alteration is an accepted feature, and then there's the fact at trying to go sufficiently north anywhere in the zee will get you to one of two places: Avid Horizon or Frostfound, and that the zee stretches to the east without end.
    The unterzee has no northern shore. Space is forbidden. Time contracts to a single frozen instant. There is only one way North.
  • Alien Lunch: You will probably need to resort to eating the various monstrosities that attack your ship at one point or another. Results will vary very, very wildly, going from heavenly to so disgusting tasters have been known to end their lives immediately after tasting without another word, and that's not getting into the various horrible poisonings.
  • Alien Sea: The Neath does not follow all of the same physical laws as the Surface, and its zee is coloured between black and green.
  • Anarchy Is Chaos: The Anarchist faction, though disjointed, is ultimately after this. The player can choose to assist them. This does not turn out well for London.
  • Ambiguous Gender: Like in Fallen London, the player can choose to not declare a gender for their Captain. The game's writing style also likes avoiding gender specific pronouns unless absolutely necessary leading to a lot of characters of mysterious and indistinct gender. A conundrum perhaps lampshaded by the very definitely ambiguous Alarming Scholar.
    • Isery on the Isle of Cats is another rare example where the ambiguity of their gender is directly brought up.
  • An Entrepreneur Is You: It might not pay so well as exploring distant kingdoms or hunting pirates, but most captains will spend at least some time ferrying goods and passengers between ports.
    • Certain trade routes, such as delivering mushroom wine to the Empire of Hands, exchanging it for coffee beans, exchanging ''them'' for parabola-linen and finally selling it in London or Dahut are some of the quickest ways to rack up obscene amounts of Echoes.
  • Androcles' Lion: If you've played along with the Monkey Foundling's little game and treated her well (and have not yet received her as a stowaway), she will come to your rescue in the Tomb of the First Emperor.
  • Arc Number: As in Fallen London, the number Seven comes up rather frequently.
  • Arc Words: "Lose your mind." and "Eat your crew." are exactly the same words you see when you reached Kingeater's Castle and are exactly what you do according to the logbook. Fortunately, it is not mandatory to do so.
    • "All shall be well, and all manner of thing shall be well." This specific phrase, in many various forms and variations, carries over from Fallen London and crops up in many different events.
    • "Is there a sea more sunless?" Doubles as a Sequel Hook.
  • Ascended Meme: Ratsending. One Fallen London player decided to amuse themselves by using that game's basic gifting system to send the lead dev thousands of rats, fifty at a time. The mythos of transported rats expanded by degrees and infected the spinoff game; a Pneumatic Ratsender is now available as a ship component. And then there's Nuncio, where said player designed the place.
    • One of the port events on Nuncio features a direct reference to this, with your captain finding a sack of dead rats washed up ashore among all the other lost mail, marked with the words "ACCEPTING NO FURTHER" and an address of "someone of importance".
  • Ascend to a Higher Plane of Existence: The Exaltation semi-secret ambition. Whatever, precisely, you end up doing, it's enough to get a brief salutation from all the gods of the Zee.
  • Attack of the 50-Foot Whatever: Oversized crabs, fish, jellyfish, eels and such make up much of the zee's monster population, inevitably leading to this trope frequently being enacted on the player. One of the methods of resolving the siege of Nidah in the Immortality ambition's ending is to employ Temtum, a giant crab to end all giant crabs, as a living siege engine.
  • Awesome, but Impractical:
    • The Icarus in Black cannon. No ordinary zee-monster can endure a shot from it, and even the 'bosses' Mt Nomad and the Tree of Ages will fall in at most two hits. The catch is that this cannon does not fire normal ammunition, but rather Doomed Monster-Hunters, who can only be bought for a Captivating Treasure, Searing Enigma (which are both valuable trade goods costing 1000+ Echoes each) or Element of Dawn (which is even more exorbitantly expensive). Because of this, Icarus in Black is impractical for general usage, being limited to very specific situations. Unless, of course, you can afford 1000 Echoes per shot.
    • The Caminus Yards 'Compulsion' engine, the second most powerful in the game (after the Fulgent Impeller). It increases your Engine Power by 3500... and comes with no bonus to fuel efficiency. Since engine power increases fuel consumption by an even larger amount that it does speed, this engine (which costs a considerable 5000 Echoes and can't be sold back one you have the Fulgent Impeller) will burn through fuel at an alarming rate to make it most of the time not worth the lowered Terror gain and supply consumption that come with speed. As a result it is usually better to stick to the Serpentine or one of the weaker engines before you can get the Fulgent Impeller (which has 50% fuel efficiency to compensate for its massive power).
    • The Eschatologue-class Dreadnought. While it boasts the same firepower and more Hull and Hold compared to the Maenad-class Frigate, the Eschatologue is slower, has huge negatives to Veils, and has a massive Crew requirement (which means it will eat supplies like none other). In addition, the prohibitively expensive cost of the dreadnought (30000 Echoes) is better spent on adorning Your Lodgings with heirlooms or having a huge stockpile of money to pass to your scion. Realistically, the frigate has everything you need. On the other hand, the Dreadnought is extremely powerful in terms of combat, and if you feel the need to sail the oceanic equivalent of a Monster Truck, you may consider upgrading.
  • Bad Boss: You, potentially. Several storylines are most easily advanced by sacrificing your own crew, with zero indication that they've done anything to deserve it. Then again, considering some of those storylines your crew actually expects this, and will be freaked out if you start getting soft. Feeding a zailor to a zee-monster that was trying to lure you lowers Terror precisely because they saw you're serious about discipline (that zailor was a known troublemaker), while pardoning certain slights will raise it because the Capn's going soft.
  • Bad Santa: Mr Sacks, The Crimson Beast of Winter, is not your friend. He does not hand out presents - the people of Fallen London are supposed to give presents to him instead.
  • Body Horror: Many instances of all sorts all across the Unterzee, but the Shapelings and Snuffers and the Fathomking stand out in particular, and then there's also the Starved Men of Godfall, formerly living on the Neath-roof.
  • Bomb Throwing Anarchist: A faction of these present both in the Neath (including both London and the Khanate, in Khan's Shadow, as well as the Iron Republic) and on the Surface, one of the competing powers the player can help or hinder and fairly period-accurate. Notable for taking a few steps further than their real-life counterparts by seeking to overthrow the Judgements - that is, to say, the stars themselves!.
  • Border Patrol: Going off the any edge of the map will lead to a story event which leaves you, your ship and your crew the worse for wear and returns you to a nearby port. The output of each cardinal direction is different, and each one leaves you with its own mark (all of which are needed to pursue the Golden Ending):
    • Try to go too far North, and after days of fruitless, freezing travel you will lose half of your crew and arrive back at either Avid Horizon or Frostfound as there is only one way North.
    • Zailing South through Adam's Way, you'll find the Mountain of Light bleeding its horribly corrosive (to metal ships) blood into the river, and you have to make a Veils check. Failing kills you, succeeding costs you all but one crew member (i.e. yourself)note  and one Hull point in exchange for a few goodies and the Touch of the South. You return to Apis Meet, now needing to limp home without touching anything lest you die.
    • Too far to the East, and after some travelling you'll be forced to turn back by an overwhelming force of silence that threatens to crush your vessel. You end up at either Irem, Kingeater's Castle, Hideaway or the Gant Pole. With all the right preparations, you will be able to zail on - triggering the aforementioned final ending.
    • Try to go West through Barnsmore's Gap, and the Dawn Machine will Mind Rape you and your crew, forcing you to return to the Grand Geode.
  • Bragging Rights Reward:
    • You have to complete a very long quest line to obtain the Leucothea-class Steam-Yacht. When it is completed, chances are you have been around the map enough and earned enough money to buy the superior Caligo-class Merchant Cruiser or the Maenad-class Frigate. If you know what to do for the quest and bee-line for it, you may get it before those two things happen, but you'll probably upgrade to either of those two ships.
    • The Zong of the Zee is this if your end goal is to become a great explorer. It grants massive stats boosts across the board, but in that ambition the entire point of the campaign was to obtain it in the first place, meaning you've already won the second you get it. Anything you do with it after that is just killing time before you go home and retire (unless you decide to abandon that ambition and go ahead with founding your own colony).
  • Brutal Honesty: The "Wounding Truth" quality counts how many times you've chosen to tell people the truth, no matter how painful it is.
  • Bullfight Boss: While every boss is capable of heavy ranged attacks, the Tree of Ages' particularly slow turning speed makes avoiding its devastating long-rage attacks by getting close, goading it to charge and continuously dodging it while chipping away at it with your deck gun the optimal strategy for defeating it. This also makes it the easiest boss to defeat, possible even with starting equipment.
  • Call a Hit Point a "Smeerp":
    • Your ship's stats are all named for Fallen London's mysterious rulers, the Masters of the Bazaar - Iron for attacks, Mirrors for observation and illumination, Veils for speed and concealment, Hearts for healing and morale, Pages for knowledge and diplomacy.
    • Your Hull score is essentially a hit point meter; in combat it's usually what soaks up attacks, and when it hits 0 your ship sinks.
    • Crew, which functions as currency in some places as well as an overall health meter for land encounters. If your Crew reaches zero, your ship suffers a Total Party Kill. However, even with just 1 Crew remaining, you can still talk to all of your officers. That doesn't change the fact that one more death renders your ship a lifeless derelict.
    • Wounds for your captain, and your captain alone. Three will kill you, and unlike Crew your Wound tolerance can never go higher. Thankfully the game will assume your Captain hides behind your expendable grunts in most on-foot engagements.
  • Chest Burster: Elderly Tomb-Colonists sometimes appear to start incubating a giant moth inside of their chests, which uses them as a cocoon and causes them to die when it emerges. It is not fully clear whether the moths simply infest their bodies with their young or whether it is, in fact, a way for the Tomb-Colonist to be "reborn" and extend their life further.
  • Choose Your Own Adventure: Everything other than directly controlling your ship is done through a digitized gamebook format.
  • Church Militant: Abbey Rock, the coastal convent-fortress of the martial Sisterhood, and Godfall, home to the boisterous pirate-monks who follow the ways of "St Stalagmite." The admiralty even classifies the Abbey Rock convent as a military instillation.
  • City on the Water: The New Khanate's cities are variations on this style: Khan's Heart and Khan's Glory form a stately City of Canals on a series of artificial islands, while the other side of the Enemy Civil War, Khan's Shadow, is a colossal assemblage of ships roped together.
  • Cool Boat: Several, including the trimarans of the New Khanate; the partly-organic Cladery Heart; the submarine Irrepressible, with its irrigo-cannon and breakfast-pit; and the dreaded Tree of Ages, crewed by giant spiders. Even your own ship might count, if you buy enough upgrades. The Zubmariner expansion adds zubmarines. They can dive, allow one to truthfully state "I own a submarine," and if they're anything like Irrepressible they'll have a dedicated breakfast nook.
  • Cosmetic Award: Beating the game with the Invictus Token does nothing other than prove you never used a manual save slot.
  • Dangerous Forbidden Technique: Several officers' storylines involve making such discoveries. Sometimes, you'll have the choice to help them pursue it, with all attendant risks, or to take a safer, less rewarding option.
  • Dark Is Evil: The Neath's darkness, due to the way the 'verse works, is occasionally noted to be actively corrosive to reason and reality, and shining a light upon it restores reality and sanity to the world.
  • Darkness Equals Death: In a similar system to Amnesia: The Dark Descent, extinguishing your ship's lights can help you hide from enemies and creep past zee-monsters without waking them, but the darkness prevents you from navigating or seeing foes clearly and drains your crew's Sanity Meter.
  • Death Is Cheap: Subverted for your Captain. If you die, the best you can hope for is to become a Drownie, and even that's not a given. Played straight for your Officers, however; regardless of whether they went down with the ship or met their end during their questline, they'll always return alive and well for your next Captain to recruit. Justified in-universe, as death is very rarely permanent in the Neath.
  • Defeating the Undefeatable: The Presbyteriate is likely the most dangerous place in the Neath, and save for its coastal settlements is rightfully considered untouchable by the other major players. Captains seeking immortality will raise an army, march right up to the walled city of Nidah and execute its ruling council.
    • Two more minor examples are the Tree of Ages and Mt. Nomad, considered by many to be impervious scourges of the zee.
  • Demonic Possession: Though not by actual demons (despite the setting featuring them as a somewhat common race in the Neath). The dream-serpents, particularly the Fingerkings, are a constant danger to Neath-dwellers, using mirrors to enter unsuspecting dreamers and perform a hostile takeover. At least two recruitable officers' stories revolve around finding ways to defeat them or ward them off.
  • Deus Est Machina: The Dawn Machine is, for all intents and purposes, a fully-functioning artificial god.
  • Difficult but Awesome: Obtaining a Zubmarine conversion in the eponymous DLC, while not really standing out among the game's many, many other difficult tasks, requires finding rare components and fairly extensive exploration of the ever-dangerous zee. The ability to dive under the zee-surface in your ship is awesome by itself, but the depths pose their own range of both difficulties starting with limited air, navigational hazards and a constant slow terror gain and up to the Constant Companion. However, they also provide rewarding discoveries on the zeefloor, access to new settlements and a way to evade surface enemies such as pirate blockades or, vice versa, flee from underwater ones, as well as a way to truly travel the Unterzee in style.
  • Disappeared Dad: One of the possible ambitions of your captain is to find the remains of their father, who disappeared at zee. If you captain is a Natural Philosopher, their father is discovered to still be alive.
  • Door to Before: The bottom of the Shattered Citadel in Godfall drops down to the zee, allowing you to safely exit the place without having to spend Foxfire Candles to retrace your steps.
    • Successfully reaching a treasure payout encounter in the Wisp-Ways on the Mangrove College island also safely returns the player to the start without having to take any penalties navigating their way back.
    • Finding the Chamber of the Seven in Scrimshander's Ivory Archives allows you to instantly return to the main hall from it.
  • Early-Bird Cameo: Several recruitable officers first appeared as Hallowmas visitors in Fallen London.
  • Early Game Hell: In the beginning, just making enough Echoes to keep your ship consistently fuelled and provisioned can be a challenge, with a degree of luck required to find the opportunities to break out of that state. Furthermore, your starting equipment makes taking on or being attacked by anything other than bats, Jillyfleurs and Megalopses a death sentence, so be prepared to flee and hope your engine outruns the enemy or they give up the chase.
  • Earn Your Happy Ending: While the Neath is unforgiving and very easy to die in or force your captain to hang up their hat early, it is possible to achieve endings that appear truly happy. Writing the Zong of the Zee will prove your captain is the greatest explorer of their generation. There is the ambition to find your father's bones if your chosen path is Natural Philosopher, as well as the Immortality ambition and, in its own way, the Uttermost East. Of course, captains with more mundane tastes can be perfectly happy with a massive mansion and a retirement fund big enough to choke Her Enduring Majesty.
  • Easy Logistics: Mostly averted, providing much of the game's challenge. Fuel and supplies deplete at a constant rate while under way and running out of either can be a death sentence for you (especially if you run out of fuel; you will then only drift until you run out of food as well). Averted in that your Crew doesn't need to be paid after initial hiring and your officers can not only outnumber your crew but don't count against your food use.
  • Eldritch Location: The Iron Republic, freed from all laws including the laws of physics and reality. Writing a port report has your captain trying to navigate ever-changing roads while the ink on your paper is constantly shifting. When you go to submit the report, it may be completely blank or explosive.
    • The game is really chock full, in every flavor. Looking for a mysterious, confusing place that just doesn't make sense? Frostfound is for you. Looking for a place where any and all rules don't apply? The Iron Republic! A place that drives people mad? Dear God, take your pick.
    • The entirety of the Neath is one unto itself, particularly when considered in light of the setting's lore.
  • Elephants' Graveyard: The Gant Pole,note  a place where zee-beasts go to die. And not all ancient beasts of the zee swam.
  • Everyone Has Standards: The pirates on Hearthstake Island in the Empire of hands were shipwrecked there long ago and turned to cannibalism. Not to survive, simply because they longed for the taste of meat. Even then, they refuse to eat a guest. Nor will they ask you to take them home; they've all agreed that cannibalism is the Moral Event Horizon.
  • Face Stealer: If you let A Raggedy Fellow onto your ship, there's a 1 in 4 chance that he's a Snuffer, a face stealing, candle-eating being who will start killing your crew one by one and start wearing their faces, causing a plot to attempt to find the impostor before it gets out of control. Another sidequest tasks the player with hunting a known Snuffer down.
  • Fantastic Drug: Red Honey, a proscribed substance described as "too dangerous to be even properly illegal." It is produced by lamplighter bees who feed on the nectar of a particular flower that drives them to madness. It causes them to enter the minds of humans and eat memories, distilling them into the red-staining honey they produce. Every time the honey is tasted, the person it originated from suffers. Needless to say, the Ministry of Public Decency will wish to have some very sharp words with anyone attempting to smuggling it...which makes smuggling it potentially very profitable.
    • The unmodified, less addictive and inhumane version, Prisoner's Honey, has the power to physically transport the imbiber into their own dreamworld.
  • Far East: The New Khanate, though ostensibly the successors of the now-destroyed Mongol city preceding Fallen London, had long since given up the ways of warriors and nomads; their architecture and much of their visible culture is somewhat Chinese, and their overall portrayal ends up a mishmash of everything "Oriental". Somewhat justified by the fact that this perception is comparatively period-accurate for a Londoner from the late 1800s.
  • Fictional Colour: An entire rainbow (or "Neath-bow") of them. Finding examples of all seven colours is a lengthy, but very rewarding quest.
  • Final Death Mode: Unforgiving Mode only allows a single save, which is automatically overwritten upon death.
  • Fixed Forward-Facing Weapon: Several larger ships are capable of mounting a "forward" class of weapons. It is typically much more powerful than deck guns, but has a much more limited firing arc. Some ships can mount a fixed aft-facing gun as well to discourage chasers.
  • Flare Gun: Flares are used in naval combat - not as weapons, but to light up the enemy and allow a ship's gunners to aim. And possibly at one point to blow up a zeppelin; to be fair, it uses hydrogen, so a flare would definitely do the trick.
  • Fling a Light into the Future: A valid gameplay strategy. After establishing a will (and maintaining it with each heir) it's possible to transmit a limited amount of wealth, equipment, and stats to the next captain. You could potentially devote one captain's entire life to buffing the heir.
  • Fragile Speedster: Cutters are the smallest, lightest and least well-armored ships available - which makes them terribly fast. That being said, the game is deadly and you don't really need to take unnecessary risks to go fast. Unless if you're trying to get the Touch of the South, which reduces your Hull and Crew to 1: the low Hull capacity of the Cutter doesn't matter since you only have 1 Hull point anyway, and it only has a crew capacity of 5, which can be reduced to 2 with the WE ARE CLAY auxiliary item, meaning that you can still sail at full speed with 1 Crew and don't need to limp to London at half speed. There's also the Stymphalos-class Steam Launch, but it is not recommended to use this One-Hit-Point Wonder unless if you want to kill your current captain.
  • From a Single Cell: Downplayed and Invoked during the assault on Nidah. The Prester and company can be killed, but they're so full of vital energies that your soldiers stop fighting like soldiers and start butchering them.
  • Fungus Humongous: One of the major life forms of the Neath. The Iron & Misery Company have a station on Demeaux Island dedicated to harvesting them.
    • There's also the Uttershroom, which is the largest Mushroom in an archipelago of them and has a small village on top.
  • Gameplay and Story Segregation:
    • You can have meet someone, have a child with them, and have the child grow up and run away to zee all within the space of a single year. It makes sense from a gameplay standpoint (allowing your child to replace you when you die) but even accounting for the weirdness of the Neath it's hard to reconcile.
    • You can carry passengers and recruit officers with special abilities and stories to sail with you. They never count toward your crew total, they require no supplies to survive, and they are never harmed by crew death events unless the captain dies first.
  • Gaslamp Fantasy: Though Genre-Busting extends to the style of the setting as well, when considered overall it falls into the gaslamp spectrum.
  • Genre-Busting: It's best described as a resource-based survival, choose-your-own-adventure maritime roleplaying game with minor action-RTS elements as its combat system.
  • The Ghost: The three gods of the zee - Stone, Storm, and Salt - are never encountered in the flesh. It's possible they don't even exist, but several game mechanics reflecting their attention or displeasure seem to indicate they're quite real.
    • Completing the Uttermost East ending implies that the player character meets Salt in person, though exactly how that transpires is unclear.
  • Giant Enemy Crab: An ubiquitous monster of the zee, appearing in no less than four variations (including a smaller, juvenile one) across the map. The king of these, however, is Temtum, a crab the size of a big island housing the town of Hideaway on his back.
  • Glamour Failure: The Drownie city of Dahut is somehow enchanted to enthrall visitors and possibly residents to see it as a beautiful, idyllic, almost ideal mirror of London. However, it is possible to break through the illusion and see the reality of the city - its stately cathedral is a wrecked clipper ship, its crypts are a prison where people from the surface are held until they agree to be made into Drownies, its gardens are withering seaweed and the water around it is littered with the remains of victims who accidentally left the area of the sea enchanted to be breathable. Curiously enough, not only can you return to the city after seeing through the illusion, but you will be welcomed in it once again.
  • Go Mad from the Revelation: Should you bring the Alarming Scholar seven Searing Enigmas and turn them in at once with a special option, you will lose her (him?) permanently due to this. Thankfully, the interface clearly warns of this outcome in advance.
    • A humorous example occurs if you choose to progress your Zubmarine quest by giving the engineers building it an Extraordinary Implication. Whatever you casually tell them causes one to undergo a Heroic B.S.O.D., another to weep boiling tears evaporating from their cheeks and a third to quietly leave and be seen burning his collection of books on engineering in the back lot. It does, however, provide some sort of new principles or ideas that make your Zubmarine feasible.
    • This is the reason why many events increase your Terror score, since many of them involve uncovering dread secrets and Things Man Was Not Meant to Know.
  • The Goomba:
    • Auroral Megalops. Encountered near Fallen London and by far the easiest enemies in the game, with only 20 HP and dealing 2 damage per attack.
    • Jillyfleurs guard the areas slightly outside the London area, being tougher and faster but not quite enough to be a death sentence.
    • Bat swarms are frailer, but faster enemies that are usually found near Venderbight, which is very often one of the first ports you visit.
    • Pirate Steam-Pinnaces are only a little tougher than bat swarms and the Megalopses and deal negligible damage, and frequently patrol the waters close to Fallen London.
  • Government Conspiracy: The Dawn Machine - both the Deus Est Machina itself and the plans around it were hatched by a faction of the London Admiralty and government, as a way to break the Bazaar's control over London. Suffice to say that it has Gone Horribly Right.
  • Hard Mode Perks: The Unter-Unterzee is dangerous even by Neath-standards, with enemies that hit like a ton of bricks, constant terror rise, oxygen management and its habit of rearranging itself more often than the surface. As you are of but a few zubmarine captains, it also holds lucrative trade routes, bounties of shipwrecks and long-dead beasts, and has places you can go fishing.
  • Hoist By Their Own Petard: Several enemy ships will fire off flares in combat, attempting to speed up their fire rate. These speed up the target acquisition for both them and the player.
  • A Homeowner Is You: You can buy a house in London, which is needed to raise your child, create heirlooms and build the Zong of the Zee.
  • Honest John's Dealership: Leadbeater & Stainrod are the Neath's largest, cheapest, least reliable provider of ships, ship components and ship repairs. It's entirely possible that they actually want you to drown.
  • HP to 1: What happens if you successfully zail southwards, upriver from Adam's Way.
    • Reaching the final chamber of Frostfound does the same to your Sanity Meter. Fortunately, the actions taken in the chamber usually restore some or all of it.
  • Human Cannonball: The Icarus in Black has one purpose: To shoot suicidal human Monster-Hunters at giant zee beasts. The monster hunter does not survive. Usually, neither does the beast.
  • Human Resources: As stated elsewhere, crew are sometimes used as trade goods or worse. Plus the entry above.
  • I Know Your True Name: Finding "The Name Which Burns" is the first step to sailing East out of the world. Without the resulting Chain of Deals, the physics-defying silence will threaten to crush you ship and force you to turn around.
  • I'm a Humanitarian: Always a risk when lost at zee, with limited supplies and a cook who's going quietly insane. And then there's Unaccountably Peckish...
  • Immortality Seeker: You might become one if you choose the Immortality ambition.
  • Infinity–1 Sword:
    • The Serpentine, which is the second-best engine in the game, is also relatively easy (though not guaranteed) to obtain, compared to the Fulgent Impeller, which is far better but requires an extremely long and drawn-out quest chain to get.
    • The Maenad-class Frigate isn't as tough as the Dreadnought and doesn't have as large a hold, but requires a smaller crew (using fewer supplies), is slightly lighter/faster, but still being large and powerful enough to complete late-game missions, and is much cheaper compared to the obscene Echoes cost of the Dreadnought. The Steam-Yacht, meanwhile, has better stat bonuses but isn't as tough, only allows a deck gun and can only be obtained through an extremely lengthy quest.
    • The Caminus Yards Heart-Ender and the Cotterell & Hathersage 'Majesty' forward-facing weapons are roughly tied for second most powerful option after the Memento Mori (Heart-Ender dealing slightly less damage to ships but greater damage to monsters and Majesty doing equal damage to both), available to you without any prior requirements and at a fraction of its cost (the Majesty being available for a laughable 400 Echoes).
  • Infinity+1 Sword: The Memento Mori, the Fulgent Impeller and the Zong of the Zee are Infinity+1 Forward Gun, Engine and Auxiliary Equipment, respectively. Obtaining the Memento Mori requires a fairly long quest chain, the Fulgent Impeller requires an extremely long and drawn-out quest chain, while the Zong of the Zee just requires an obscene amount of resources, especially secrets.
  • Interface Spoiler: The trading interface shows the existence of certain items and trade goods before you're likely to find them in play. Notably, the end reward of the Genial Magician's storylet is shown, even before you recruit him.
  • Island of Mystery: Would be more straightforward to list the ones that aren't. Irem probably the pick of the bunch for being literally inexplicable.
  • Istanbul Not Constantinople
  • Item Caddy: The Caligo-class Merchant Cruiser isn't very expensive (costing only 8000 Echoes) and has 120 Hold, the largest in the game (compare to the Frigate, which costs 15000 Echoes and has only 70 Hold, and the Dreadnought, which costs 30000 Echoes and has 100 Hold). This vessel allows you to greatly capitalise on trading and greatly reduces the difficulty of acquiring enough Hold slots for certain quests that require a lot of materials (the purchase of Dawn's Law and the construction of the Fulgent Impeller being fine examples). The two drawbacks are that the ship isn't really suitable to combat due to the lack of a Forward cannon mount, and is as heavy as the Dreadnought, so travelling takes a lot of time.
  • Joke Item: The Stymphalos-class Steam Launch, a One-Hit-Point Wonder of a ship with a tiny hold, no crew quarters, and a massive stat penalty. Normally, you'll only ever get one if you somehow survive losing your existing ship, but you can buy one in London if you really want to. Lampshaded in the game:
    Possibly there's a reason you might want to set to zee in a boat the size of a dining-room table. Possibly.
  • The Law Firm of Pun, Pun, and Wordplay: Many firms in the naval industry have such names: Cotterell & Hathersage, Leadbeater & Stainrod, Iron & Misery Company, Soothe & Cooper...
  • Lampshade Hanging:
    This is what they call Prisoner's Honey, wrung by the lamplighter bee from the exile's rose. "I wonder oo made up all these names," remarks Able Seaman Cargit. "Someone with a slight too many books, I'm finking."
  • Language of Magic: The Correspondence, the language of the Bazaar and possibly the Judgements. Overlaps with Words Can Break My Bones and Black Speech, since actually reading and speaking it may set things (such as the reader) aflame, its sigils are capable of killing or brainwashing people, and opponents such as the Lorn-Flukes and Mount Nomad actively use it as a weapon for naval combat.
  • Laser-Guided Karma: The Delightful Adventuress. It's hard not to find the resolution satisfying, provided you allowed her sidekick to have a say.
  • Leitmotif: Most of the game's soundtrack, in the form of a song appropriate for each area playing whenever you get close to it.
  • Lemony Narrator: The narration can become extremely dry, snarky, or understated depending on the circumstances.
  • Let Us Never Speak of This Again: Your captain's encounter with the Monkey Foundling is detailed in their journal using the following three words: "THIS. NEVER. HAPPENED."
  • Level Drain: Some encounters and adventures across the Zee can deduce points from your statistics scores. In particular, when navigating Frostfound's fortress, you can opt to drain a point out of each of your primary statistics in order to bypass very difficult skill checks. Other point-deducing options sometimes occur at important points of storylines, the most likely one to be lost being Hearts.
    • The goal of zailing into the Uttermost East is the king of these. Over the course of the quest chain enabling you to do so, you'll take many hits to various stats, and the voyage itself will drop all of your statistics save for Hearts to one, meaning that you won't be able to boost your next captain with them.
  • Literary Allusion Title: To Kubla Khan. Doubly appropriate, as Xanadu is of established importance in the setting's lore.
    Where Alph, the sacred river, ran
    Through caverns measureless to man
    Down to a sunless sea.
  • Light Is Not Good: The Dawn Machine is an artificial sun that gives the only day-bright light in the entire zee - and it is not good or nice to any degree, its objective seeming to be total domination of the Neath. Anything associated with it causes your crew to get extremely nervous and frequently fall into raving about "the sun, the sun!", and the false dawn it creates is always grounds for an Oh Crap! reaction; its Glorious fleet is ruthless, piratical and very well-armed in their glittering ships.
    • Real sunlight is actively hazardous to Neath-dwellers due to the rules of the setting's reality. It can kill someone who'd sustained lethal damage in the Neath but did not die because of its Death Is a Slap on the Wrist nature, and to any normal person who spent too much time underground (such as the player character and their crew), sunlight is a withering, burning force that can suddenly kill them, wound them and/or drive them to madness. This makes the zee around Aestival, an island located under a breach in the Neath-roof through which sunlight can shine, one of the most dangerous places in the game and rightly feared by zailors.
      • This is because the Sun, as well as all other stars, are Judgements, the setting's Physical Gods, and the light they emanate is their will and law. The Neath, being hidden from the direct light of the Judgements, is exempt from "a dozen or so" of such laws, including some of the rules of life and death, and creatures that spend too much time outside of those laws become increasingly harmed by the light. As further icing on the cake, the Judgements are not benevolent entities, being ambiguous, indifferent and neutral at best and malicious at other times. In this sense, in the world of Fallen London and Sunless Sea, the stars are Chtulhu.
  • Lightning Bruiser: The Fulgent Impeller converts your ship into this, regardless of whether you're zailing a cargo steamer or a dreadnought. The Serpentine can do the same for the corvettes.
    • Among the monsters, the Blue Prophets possess serious amounts of health, deal respectable amounts of damage have and the speed and mobility of zee-bats.
  • Living Ship: The Cladery Heart, a colossal, living heart, clad in iron and set to sea.
    • The Tree of Ages, a huge congress of sorrow-spiders acting as a powerful, respawnable boss.
    • One of the options to deliver the Seven Against Nidah and their forces to their destination is to navigate the river to Nidah using Polythremean living ships.
  • Luck-Based Mission: Several challenges are purely luck based, but fortunately they are never mandatory and the player has an idea of their odds when choosing to try them. More generally, surviving the Early Game Hell requires a certain degree of luck in the zee's alteration, coupled with some existing knowledge of the game.
  • Macrogame: When a game ends, the player can begin a new game with a choice of bonuses, including skill boosts, maps, officers and weapons. Wealthy captains can also write a will, allowing their house and some of their wealth to be passed on.
  • Mad Artist: The Set, a group of highly eccentric and vicious artist-pirates. One of their former members, the Merciless Modiste, can be recruited as your ship's first officer, and she is excellent with both clothing and murder. She tells you a few tales of the rest, all of them psychopathic or merely insane. And then there's the Irrepressible, their dreaded flagship zubmarine. Built for form and function, and with a main gun that fires mind-destroying colors, it's feared with good reason.
    • The Rosegate underwater cigar shop is run by an extremely eccentric tobacconist bent on creating an underwater cigar, which seems to require very unsavoury and unethical means and ingredients. Further underlined by the fact that actually going through with assisting him enough to complete his cigar nets you a Supremacy point with the Anarchists, his final destination being the Iron Republic and cryptic warnings about his work risking "setting the zee aflame".
  • Mad Scientist: In the Neath, it's easier to count scientists who aren't mad. Even the Player Character with the Natural Philosopher background seems to qualify.
  • Madness Mantra: If you get near the Dawn Machine, the logbook will simply say "THE SUN THE SUN THE SUN THE SUN THE SUN THE SUN THE SUN THE SUN THE SUN". This is even repeated in the Dawn Machine's Supremacy quality description.
  • Mega Maelstrom: Whirlpools appear as environmental hazards; they're not hard to avoid, but ships that sail into one will have their hull battered until they can overcome the currents and escape.
  • Men Are the Expendable Gender: Strongly averted. While your generic crew don't have names, most of the gender-specific descriptions refer to them as female and they are quite likely to die at zee.
  • Mighty Glacier: The Eschatologue-class Dreadnought, as the description reads. Tied for the heaviest and slowest ship in the game, and absolutely destroys your Veils score, since trying to be sneaky with a ship that size is doing it wrong. In return, it boosts your Iron score (your damage) tremendously, has all three gun slots available to boot, and it's basically indestructible in terms of hull.
    • A remarkably literal example are the Lifebergs; although not true icebergs, they're still huge, mobile masses of ice and unknowable substances of the Neath that are actively hostile to ships, moving quite slowly but dishing out heavy ramming damage and boasting a remarkably high health point count.
    • Most of the monsters of the Zee, both above and below the surface, generally operate as either this or Lightning Bruiser.
  • Mind Screw: The nature of the setting as a Gaslamp Fantasy Lovecraft Lite Cosmic Horror Story naturally leads to these being a common occurrence. The most shining examples are the entirety of the fortress of Frostfound and Irem of the Pillared Sea, locations which mess with your captain's head a lot.
  • Mooks: Pirates and zee-beasts are always referred to by generic descriptions. Ships with names are almost always neutral trading vessels except for the Eater of Names, the Tree of Ages and the Irrepressible.
  • Multiple-Choice Past: You decide your captain's background, social title, and ambition at the beginning of each game. These influence a number of things throughout the captain's time - which of your stats is initially higher, your starting officer, victory conditions, and a handful of other story directions. You can, however, opt to defer these decisions until a later point in the game.
  • Multiple Endings: If you don't die at zee, depending on your Ambition, you might end the game either by retiring from zee-faring to a life of luxury, becoming London's most venerated explorer, finding and burying your father's bones, taking over Nidah and gaining immortality, being rewarded with one of the kingdoms of the Presbyterate, founding your own kingdom at Aestival, or sailing beyond the Zee out of the world to the Uttermost East. There are also Non-Standard Game Overs during which you accompany the Merchant Venturer and pass through the Avid Horizon to the High Wilderness, or become the lover of Lady Black.
  • Mundane Luxury: For Londoners, foodstuffs produced from the surface such as rye bread, cheese, and fresh fruits and vegetables are considered to be absolute luxuries. If you resupply while in the surface port of Naples, your crew will all look hungrily at the surface food that you purchased.
  • Mushroom Man: The blemmigans, while not humanoid in shape, act somewhat human-like and possess enough intelligence to hold what seems to be philosophical debates in their colonies and even learn (and critique) written poetry.
  • The Mutiny: A ship's crew may mutiny against their captain if Terror grows too high. If they can't be talked down or beaten down, game over.
  • Nautical Folklore: Used heavily In-Universe, as Zee-farers are extremely superstitious for a damn good reason. Even if your captain doesn't believe, playing along is very good for morale.
  • Nightmare Face: The Tides of Appetite are full of writhing, gnawing faces; given that Polythreme is a place where everything is alive, it has quite a few as well. The island as a whole looks like a skull, and many of the districts have an uncomfortable resemblance to organs.
  • Nightmare Fuel - In-Universe: The Unterzee is full of things that can and will traumatize your captain and their crew, from unsettling events to Terror-raising devastating monster attacks. If your Terror score is high enough, your crew starts having recurring nightmares, and should you return to London with your Terror score above 50, so will your captain.
  • No Indoor Voice: The pirate captain on Hearthstake island in the Empire of Hands. Every word he says is in caps, the narration even says that he's louder than his blunderbuss.
  • No Party Like a Donner Party: If you're low on food, your crew may resort to eating each other to survive. Furthermore, there are several places where cannibalism is practiced, where you may be introduced to the practice. If you've partaken before, you can actively choose this resort should supplies run out. Some storylines clearly show this as a Moral Event Horizon.
    "Starvation walked the ship. We were merciful; our knives were sharp."
  • Nonstandard Game Over: There's several endings that aren't part of your ambition that you can achieve. Unusually, these gives you items that will assist you in your future playthroughs. For instance: Going through the Avid Horizon with the Venturer, or stealing the Emperor's Zeppelin and going East. There are also some more traditional Nonstandard Game Over, like choosing to deliver the Monkey Emperor's Wrath (which is part of things you need to do to get the Zeppelin), but chose to return to London instead when you were warned to not go back.
  • Nonstandard Skill Learning: Secrets serve the role of skill points, but they're also a commodity that can be traded, or expended as a part of quests. To actually turn a Secret into a stat increase, one needs to trade it to an Officer who specialises in that stat. Oh, and the Pages stat increases the rate of Secret accumulation, but no Officer increases Pages higher than the beginner range - it can only be raised through questing.
    • Crafting an unusual item, like an Anatomical Cabinet (from a bunch of skulls and other relics) or a Whispering Trophy Case (from strange catches in the Unterzee) requires seven secrets, boosts a skill by seven points, and gives you an item which boosts that skill by another seven.
    • Completing certain encounters and choosing certain options upon defeating monsters is another way to raise your captain's skills... or lower them. Exceptional, one-time storybook events can raise or lower your statistics by double digits, defeating certain bosses can award you up to five points (usually Iron), and looting some monsters increases your skill by one.
  • Noodle Implements: Some of the Merchant Venturer's requests can get... odd. Some of them make sense, but why does he need romantic literature for a trip through the Avid Horizon?
    • Possibly they are needed in the ritual to open the gate. After all in the deepest matters of the Bazaar, look to love. Always.
  • Ocean Madness: It has less to do with the fact that the zee is inherently maddening and more to do with the fact that it is dark, monster-infested, and prone to rearranging itself, but Terror will be your constant sanity-draining bane.
  • Old Save Bonus: You can connect the game to your Story Nexus account, and doing certain new storylets in Fallen London with a linked account can give captains in Sunless Sea starting advantages.
  • Open Secret: Zubmarine travel is illegal, not that it matters because there is nothing of interest down there anyway. Once you help the Fierce Philanthropist open her zubmarine workshop, it starts a gold rush of sorts and the Admiralty seems to stop caring in any practical manner.
  • Overdrive: Players can dump extra coke into their boilers to drastically increase speed for a brief time. However this is something best done only rarely, since it is very wasteful of fuel, and doing too frequently risks the engine running too hot and causing all sorts of bad things.
    • There is a small chance for the overheated engine to push this further and actually gain a massive increase in both power and fuel economy for a short while.
  • Our Mermaids Are Different: There're the Drownies, undead-like beings capable of enthralling songs and illusions and always seeking to turn more humans into their kind. There are also the monstrous "serpentus sirenesis", encountered while exploring some islands, who have tails shaped uncannily like a human woman and lie in wait at the shore while the main body of the serpent is hidden underwater.
  • Phantasy Spelling: Certain words starting with 's' start with 'z' instead in the Neath: 'Unterzee', 'zailor', 'zubmarine', and so on. There's a reason, which is basically that several plays at Mahogany Hall played off the Dutch accent of one of the greatest explorers of the Zee, and the zailors themselves loved it and stuck with it. Non-zailors are advised to be careful with their 'z's, however, as excess usage annoys them.
  • Piñata Enemy:
    • Pirate Frigates, and their zubmarine counterparts, Corsair Undergalleys, net you 1-2 units each of supply and fuel, plus a random loot item like those you get from smaller and larger vessels, and sinking them takes little effort once you can afford a decent weapon + Iron skill. If the Random Number God is feeling unkind, though, all you'll get is a loot item worth a few dozen Echoes.
    • Beloveds are fairly slow, not especially dangerous underwater enemies who will always provide 2 supplies, some hunting trophies, and possibly extra food when killed. Apparently they're quite good eating.
    • Two tougher, but even more valuable pinatas are Lifebergs on the surface, and Thalattes below. Both can take a beating, and can deliver a lot of pain, but are hugely profitable once dead; both offer either plentiful supplies or a ton of echoes' worth in valuables
    • The ultimate pinata enemy of the game is the Lorn-Fluke. A savvy zee-captain can keep their ship at the right distance from a fluke so that it can be brought down quickly and with no or very little damage done to their ship, and the colossal fluke-core, a guaranteed drop from the surface Flukes, is worth 500 echoes if sold directly or a hundred more than that if traded for a Judgements' Egg in the Iron Republic. In addition to that, successfully passing a moderate Pages check also nets three free Secrets for each fluke - perhaps the easiest and fastest way to farm Secrets in the entire game. They also happen to have a wide spawning area, making farming them an easy and very profitable endeavour for those skilled in zeefighting.
      • The Dawn Fluke, found underwater near the Dawn Machine, can yield an even more profitable piece of loot through a mild Pages challenge - a Searing Enigma, worth a thousand echoes if sold to the Scholar in London. Like all enemies, it respawns.
  • The Power of the Sun: Sunlight is a potent force to the denizens of the Neath, able to kill or grievously harm them should they be exposed to it for any significant time. This is because sunlight, as well as the light of any other star, is the means by which the will of the stars, the Physical Gods of the 'verse, is enforced. In this sense, the Power of the Sun is the main underpinning of the 'verse's reality.
    • The Dawn Machine brings its own twist to the trope, its light primarily making creatures that come in contact with it Brainwashed and Crazy.
  • Power Glows: The ships and beasts touched by the Dawn Machine all emit a yellow-orange, incandescent glow, and are some of the most powerful enemies you can find at zee.
  • Plunder: Fighting enemy ships to defeat generally leaves them in no condition to be captured, but something can usually be salvaged before they sink, especially their cargo crates. This also applies to large zee-beasts, which when killed usually float up for a while, allowing them to be harvested by the hunting ship.
  • Purely Aesthetic Gender: As is standard in Failbetter games, the Player Character can be addressed as male, female, or any of a number of other descriptors, without limiting their stats, portrait, or options in dalliances. For that matter, if you have a romance with someone in London you can eventually get a letter and choose if your character sired a child or will give birth to one, regardless of your portrait or pronouns or those of your lover. There's even an option where your lover has adopted, and a game note saying "Choose this option if you're unlikely to be either a father or mother." And then you have the option of whether the child calls you Father, Mother, or Captain.
  • Putting the Band Back Together: The Immortality ambition largely revolves around reassembling the Seven Against Nidah, the band of adventurers who attempted your quest before and failed.
  • Randomly Generated Levels: The surface of the Unterzee is divided into 36 tiles, which are rearranged for every new captain (except for the western and southern coasts). Referred to as Alteration by the Londoners, and it's understandably something newsworthy whenever it occurs. The zee-floor, which is procedurally generated except for the ports and abysses, changes even more often than the surface map does.
  • Reality Warper: The Judgements in general, as well as the Dawn Machine.
  • Real Time with Pause: Combat and zailing play out in pauseable real time. The clock stops when you have the Gazetteer open, which is usually in a port.
  • Red Shirts: Your officers are named and exempted from crew count and supply consumption. The remainder of your crew are nameless and can be blown up in combat, eaten by zee-beasts, or even eaten by fellow crew at your decision.
  • Resources Management Gameplay: Fuel and supplies are necessary to run the ship and maintain the crew, and their use and conservation must be balanced. The integrity of one's hull must also be carefully monitored, as taking damage at less than 50% hull results in (among other things) the deaths of crew. If your ship has 50% or less than its maximum crew capacity, your cruising speed will be effectively halved, which is quite bad. Worse, if your crew count is 25% or lower, your rate of increasing Terror will double.
  • Sanity Meter: The Terror and Hunger stats track the crew's mood. An unhappy crew is at greater risk of going mad, killing each other, mutinying, leaping overboard, destroying precious resources/parts of the ship, or resorting to cannibalism. Your captain will also suffer fits of paranoia, uncontrollable screaming, irrational rage, hallucinations and so on.
  • Schmuck Bait: "Do Not Do This". It is always good, honest advice. One of the locations found towards the edge of the map is a mysterious altar that's creepy even by Sunless Sea standards. Two of the options, as well as having activity descriptions that should give most players a clue, are clearly marked "Do Not Do This" by the game. Despite the fact the game has been completely honest with all advice the entire time, forums still contain confused players utterly bewildered at why their game just ended.
  • Screw This, I'm Outta Here!: How you "defeat" Mt. Nomad - as the "grand-daughter of the Bazaar" (yes, that one), it's functionally immortal... but isn't immune to serious injury. At zero Health, you inflict such a bad wound that the Genius Loci decides to cut its losses and submerge to safety underneath the zee until the next Alteration. While you can loot it, it's not you harvesting its corpse so much as sending your crew to get as much from the sinking island as they can before it is fully underwater.
  • Sequel Hook: "There is a sea more sunless", a phrase you will repeatedly encounter in your travels, particularly in hard-to-reach places. Usually it is presented as a question ("Is there a sea more sunless?", but the Uttermost East Golden Ending firmly presents it as a statement. The sequel, Sunless Skies, is already being made.
  • Shout-Out: The schematics for the Irrepressible include mention of protective measures "to guard against the bites of sharks".
    • The Finknottle Abyss. Perhaps there are newts there.
    • There's also a Shout-Out to Coleridge's The Rime of the Ancient Mariner if you ate your crew at Kingeater's Castle.
    • On the topic of the Ancient Mariner, it's possible to shoot a white bat that follows your ship. Since the white bat is sacred to the zee-god Salt, just as when the Mariner shot the Albatross, you'll deeply alarm your crew (reflected in huge jump in Terror) and draw the ire of other powers. It's a bad idea.
    • Gaider's Mourn may be named after former Bioware writer David Gaider, known for having written stories and romances that send players to tears and allegedly feeding off said tears.
  • Silent Running Mode: Useful for evading enemy ships and slumbering zee-monsters - unfortunately, it requires cutting the lights, and Darkness Equals Death.
  • Smash Mook: Most zee-monsters fight this way. Once you're spotted, they'll continue to charge at you until either they or you are dead, or when they can no longer spot you. Except the most powerful monsters, which have additional attacks.
  • Songs in the Key of Panic: When you reach 90 points of Terror, an extremely tense song replaces whatever was playing at the moment, and will not stop until you go below 90 once more.
  • Soundtrack Dissonance: Approaching the Iron Republic, that bastion of absolute, reality-defying lawlessness and general inexplicably strange events, is accompanied by a joyful Irish-esque tune that'd be more fitting for an actually pleasant place. Perhaps this place even overwrote whatever laws of narrative made this inappropriate.
  • Starfish Aliens: The Lorn-Flukes, the Rubbery Men and several other species of the Neath did not originate on Earth, but came there together with the Bazaar from another world elsewhere in space.
  • Starfish Language: Whatever language the Rubbery Men speak, humans cannot seem to make heads or tails of. On top of that, the Rubbery Man recruitable as your officer seems to be one of a very few able to speak a human language.
  • Steampunk: Curiously zig-zagged and downplayed for the most part. The parent game of Sunless Sea defined itself and the setting it shares as non-steampunk, eschewing outlandish technological inventions and other tropes typical of the genre in favour of magical and mystical features, some of them distantly approaching Science Fantasy territory, and even explicitly referenced the steampunk genre in a work of in-game fiction its players could create. Sunless Sea itself, however, features many things more typical of steampunk, particularly anachronistic and potent technologies like thermobaric weapons, undersea towns created and maintained without relying on magic and normal seagoing ships modified with extendable overhulls that completely transform them into zubmarines.
  • Submarine Pirates: The Pianolist, one of The Set and captain of the Irrepressible. When exploring the Unter-Unterzee, you might also encounter Corsair Undergalleys and the Wreckships of Wrack.
  • Supernatural Eyes Of Gold: People touched by the Dawn Machine have gold-flecked eyes and light-infused glowing irises and are commonly described as "bright-eyed". For this reason, most of them choose to wear Sinister Shades and can be identified by them. The Dark-Spectacled Admiral averts this, though he is keenly aware of the Dawn Machine conspiracy.
  • Survival Sandbox: The game is basically a Wide Open Sandbox in a procedurally generated world, focused on resources management, and including permadeath.
  • Temple of Doom: The Vault of the First Emperor was built by monkeys who attempted to imitate this trope as seen in human culture, and as such is something of a Deconstructive Parody of this sort of level:
  • That's No Moon!:
    • Lifebergs and Mt. Nomad look like bits of island. They are not. What they are is large, malicious, and extremely hazardous to shipping.
    • Mt. Nomad, the Lifebergs' much bigger, much more powerful sister, an actively hostile mobile mountain stalking the seas.
    • There's additionally The Eye, a huge eyeball embedded in the zee-floor. And based on the surroundings, this leads one to believe at least a fair bit of the zee-floor is a part of this thing's head.
  • The Dog Bites Back: The only reason the Delightful Adventuress loses her attempt to cheat you and the Mayor of Port Stanton out of your shares of the Legacy of the First Emperor is her casual betrayal of her Dumb Muscle sidekick, the Unfinished Clay Man Barnabas and her poor judgement of just how strong, persistent and durable he is.
  • The Secret of Long Pork Pies: You can have some really satiating food at the Chapel of Lights, for free! There is a high chance of getting the Unaccountably Peckish menace from this, however...
  • Things Man Was Not Meant to Know: A trade good of the game, coming in several varieties of potency. The Dread Surmise in particular is implied to be this.
  • Threatening Shark: Bound-sharks are enormous and attack any ship that gets too close. Particularly Tormented Bound-sharks epitomize this.
  • Too Awesome to Use: Sure, the Icarus in Black is such a powerful device it can two-shot Mount Nomad, but those monster-hunters it fires are expensive as hell, and finding places where to hire them in the first place is quite rare too. So aside from Mount Nomad and possibly an emergency, it's mostly useless.
  • Turtle Island: The Chelonate, a city built on the floating carcass of a colossal turtle. Its inhabitants subsist largely on the the products of the zee - they wear sharks' skin and drink their blood.
  • Underground Monkey: Angler Crabs come in three variants: the red Western, the blue Eastern and the orange Elder.
  • Underwater City: All cities beneath the Unterzee, which can only be visited if you have a zubmarine.
  • Unstoppable Mailman: The residents of Nuncio are bound and determined to sort through all the mail there, no matter how insurmountable the task.
  • Weakened by the Light: Neath-dwellers are harmed by The Power of the Sun, which makes any kind of extended trip to the surface risky. However, that same risk also makes it potentially very profitable.
  • What a Piece of Junk: Don't underestimate Wreckships. They may look like the product of a half-assed salvage effort, but they can do a number on your zubmarine and are Dreadnought-level tough.
  • What the Hell, Player?: The game chastises you if you attempt to toss human passengers overboard like cargo. "Captain! What are you thinking?!"
  • Wooden Ships and Iron Men: The ships are iron with hearts of steam, but the vast, dangerous and largely unexplored Unterzee is a setting much more like the Age of sail.
    • Many islands and encounters further prove that while the ships are mostly iron, the men and women sailing them are even tougher.
  • The World Is Just Awesome: If the player makes a trip to the surface, a splash image of a sunrise is shown in place of the regular Zee map for as long as they remain.
  • World of Chaos: The Iron Republic, where men rebel against the very laws of physics
    • The Neath itself to a considerably lesser degree, being packed with many locations and objects defying reality, logic and understanding that undergo Alteration whenever your captain dies or ends the game through other means.
  • The Undead: Coming in two main, somewhat subdued flavours:
    • The Tomb-Colonists, normal Neath-dwellers who outlived their bodies' capacity to regenerate and sustain themselves but are unable to die because Death Is Cheap in the Neath. They're technically still alive and human in every sense that counts, but they're treated like undead beings, don't seem to require sustenance or even air, tend to wrap themselves in bandages to hide their withering, crumbling forms and resemble mummies or zombies, and normally retire to the Tomb-Colonies, no longer welcome in polite society.
    • The Drownies, humans who drowned and were transformed into siren-like creatures with some help from the Lorn-Flukes. They are generally neutral to other dwellers of the Neath and able to go onshore, but are capable of entrancing others with their songs to make them jump into the zee and drown and generally tend to scheme to turn more humans into Drownies.
  • Understatement: When contemplating betraying a Dapper Chap to the Hands-On Diplomat, the Lemony Narrator has this to say:
    It's safe to say this will end your relationship.
  • Wretched Hive: Several islands qualify.
    • Khan's Shadow, specifically built as a haven for all those who don't fit into the New Khanate society and dominated by anarchists, rogues and pirates. The action to compile a port report there even states "So many malcontents, so little time."
    • Gaider's Mourn, a base of zee-pirates and smugglers of all stripes, open to black market trade. Many port actions there involve getting into random fights with varying success.
    • Isle of Cats, home to the Pirate-King and the biggest farm of red honey, deals in the most forbidden of goods.
    • The Iron Republic takes this to a metaphysical level, warping the laws of nature and reality itself.
    • Even Fallen London itself qualifies to a notable degree, with extremely shady business rife in the city and around it and the remnants of authority largely powerless to stop much of it or directly complicit in it.
  • Video Game Cruelty Potential: There are many, many opportunities for the player to be callous and brutal on the Unterzee. Some island storylines, while entirely optional, outright require the player to be a cruel, sadistic bastard to progress at all. There are no real repercussions for doing so... unless, of course, your captain happens to die at sea afterwards. That, and your crew have standards; being an evil bastard tends to raise your terror due to low morale in several cases.
  • Villain Protagonist: The player, horrifically so, depending on their choices. You can potentially send unsuspecting ships to their doom to enrich pirate-salvagers, engage in human trafficking, sell trusting tourists as food to sorrow-spiders and destroy peaceful civilian ships. And then there's the poor Sigil-Eaten Navigator.
  • X Meets Y: Fallen London meets Sid Meier's Pirates!.
  • Xtreme Kool Letterz - In-Universe: Some of the Londoners attempt to imitate the zailors' Phantasy Spelling accent in order to appear cool, frequently overdoing it by replacing all of their "s"es with "z"s. This does not amuse the actual zailors.
  • You Have Outlived Your Usefulness: As part of the Immortality ambition, once you reach Nidah, you might choose to betray the rest of the Seven and seize immortality solely for yourself.
  • You Nuke 'Em: One of the ways to breach Nidah's walls is investing in experimental munitions research, which is implied to be nukes..
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