Video Game / Barotrauma

Embrace the Abyss.

Barotrauma is a 2D submarine crew survival simulator developed by FakeFish Games and Undertow Games, and published by Daedalic Entertainment. The game released on Steam early access in June 5, 2019, before getting a full release on March 13, 2023.

Players, as a submarine crew, brave the depths of Jupiter's 6th moon, Europa. The game, inspired by Space Station 13, centers around crisis and resource management, where players must contend with hull leaks, deteriorating equipment, dwindling welding fuel and ammunition for their small arms and submarine guns, and as is often the case, losing crew members to the Europan fauna that inevitably attack the sub. Or clowns who sabotage their efforts.

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This game contains examples of:

• 2-D Space: The game takes place in a 2D environment, so this is a given. Notably, tongue-in-cheek references to the world being two-dimensional are made by your crew; some crew members will ask if anyone else feels flat, and other crew members will note that "starboard" is no longer a nautical term as there is no use for it anymore.
• Advancing Wall of Doom: An optional campaign feature is Jovian radiation, which slowly progresses across the game world (similar to the rebel fleet in FTL) progressively rendering outposts uninhabitable. This acts as an Anti-Grinding feature, forcing you to advance ahead deeper and deeper into Europa instead of hanging around in the beginning areas grinding money and xp.
• Alliance Meter: The game tracks your reputation for the Europa Coalition, Jovian Separatists, Church of the Husk, and Children of the Honkmother. Doing transport or combat missions for the Europa Coalition increases your reputation with them and decreases your reputation with the Jovian Separatists, and vice versa. The Church of the Husk and Children of the Honkmother are likewise opposed. It is possible to be in good standing with everyone by balancing your missions, because reputation increase from missions is slightly higher than the corresponding reputation decrease for the opposing faction, and monster hunting and mining missions increase reputation without pissing off the opposing faction. The Captain perk that increases your reputation gain helps even further in this regard.
• Anti-Frustration Features:
  • If you somehow manage to die in a place where a rescue shuttle is not logically available during the campaign, you'll just respawn on the sub instead. There are very few locations where this applies, but dying at any point after entering the Eye of Europa will respawn you on the sub, making that section much easier.
• Artificial Stupidity:
  • You can add AI bots to your crew to substitute for human players if you're running short or just want to play solo without having to do everything by yourself. They are not very flexible in their tasks, however: you have to order them around for them to actually do anything, and even then they will focus solely on that task even if there are more pressing matters at hand, like intruders.
    • Security bots suffer from severe Suicidal Overconfidence. They will charge mudraptors and crawlers with nothing but a knife and a baton if you don't give them guns.
    • Not all is lost on them, though. They can home in on hull breaches and broken devices, fixing them in a flash, their accuracy with weapons is pretty good, and they'll immediately report situations happening on the ship that they can see, such as hull breaches or injuries. As the game develops, the AI keeps getting upgrades, making them ok addition to human crew with proper orders.
  • Creature AI isn't immune to stupidity either. Hammerheads will often become so fixated with hammering your sub that they will completely ignore a crewmember actively chasing and cutting them up with an axe.
• Badass Bandolier: Craftable by Security Officers with the "Don't Push It" talent, a Bandolier is an outerwear item that has four inventory slots, ideal for carrying stacks of ammunition. It also buffs Weapon Skill by 15 points and weapon fire rate (both handheld and submarine turret) by 25%, actively making the character more badass for wearing it.
• BFG:
  • Engineers with the late-game "Nuclear Option" talent can craft the Rapid Fissile Accelerator, an energy weapon powered by nuclear fuel rods.
  • Security Officers with the late-game "Warlord" talent can craft the HMG (Heavy Machine Gun), which fires with such force that characters with inadequate Weapon Skill are immediately knocked down by the recoil.
• Bittersweet Ending: After completing the campaign, journeying through miles and miles of underwater caves trying to outrun the Jovian Radiation that's rendering Europa uninhabitable for humans, you finally get to the Eye of Europa, which somehow ends up transporting you to the Eye of Jupiter, where you find and kill Jove, the eldritch creature worshipped by the aliens and responsible for the radiation. As it dies, it states that the time of the aliens has passed, while the time of humanity continues, before pointing out that no one will know of your sacrifice. The ending dialogue between Europa and a Jupiter base (which makes it seem as though Europa is finally able to contact offworld colonies again) notes that the Jovian Radiation is ending, reaching a nadir that means that Europa is safe again, but they have no idea why. And your submarine hasn't been seen since you left an Graff's facility.
• Bizarre Alien Reproduction: The Beasts Within update for the Steam release introduced a literal Explosive Breeder with the Hammerhead Matriarch. One blow to her pulsating head and it will violently burst out many Hammerhead Spawns. Obviously, this kills her instantly.
• Boring, but Practical: Some of the talents granted to the crew fall under this. For example, getting 100-someodd experience points for the first 3 fuel rods crafted every mission isn't very exciting, but it rewards Engineers for something they should be doing anyway, and the resulting level-ups can grant talent points for more interesting skills. Higher quality tools (wrenches/screwdrivers) and consumables (oxygen/welding fuel tanks) also fall under this heading.
• Brown Note Being: The Watcher creature is unusually docile, but bears a gigantic glowing eye that has terrible effects on the mind, generating the Watcher's Gaze affliction on crewmembers as it curiously examines their submarine. Watcher's Gaze causes confusing screen blurring, Nausea, Psychosis and a severe penalty to movement speed as it worsens. Perversely, it has the opposite effect on Europa's native life, granting crawlers, mudraptors and threshers a growing boost to their movement speed and Hit Points.
  Examining Others: "Seeming confused and slightly terrified, the patient doesn't look good. Could it be a mental breakdown? A stress reaction? There's not much you can do about it."
  Examining Self: "You can’t shake it. It will always be there, staring. Would tearing out your own eyes make it go away?"
• But What About the Astronauts?: A throwaway line for why the situation on Europa seems so perpetually desperate: contact with Earth has been lost for reasons unknown, which means the Europan colonists are effectively stranded on this Death World with no economic support from outside.
• The Captain: One of the character classes, who runs double duty as the de-facto leader of the crew and the submarine's primary pilot (as they start with the highest initial Helm skill).
• Character Class System: As to be expected for a submarine crew simulator, there are six classes to pick from, each with their own Skill Scores and Perks. They're also split further into three archetypes that have different starting equipment.
  • Captain: Starts with the highest Helm skill. This class is intended to formally represent the player in charge of navigating the sub and giving orders to the crew, and most of their campaign perks reflect this. However, the Captain also starts with a handgun, and has a talent path dedicated to becoming The Gunslinger.
  • Security Officer: Starts with the highest Weapon skill, as well as body armor, weapons and some other supplies. Their duty is to safeguard the crew from threats both internal and external (as their weapon skill also applies to the submarine's armaments), as well as keep the armoury stocked through crafting. They are especially relied upon to restrain or neutralize crew members trying to sabotage the submarine (whether these are part of Traitor objectives or just plain griefing).
  • Medical Doctor: Starts with the highest Medical skill, a syringe gun, health scanner goggles and some basic medical items. They're responsible for maintaining the crew's health and crafting supplies at the ship's Medical Fabricator, but a medic who gets the right ingredients can also craft toxins for fending off intruders, both alien and human. With talents, they can unlock the ability to splice alien LEGO Genetics into their crewmates.
  • Engineer: Starts with the highest Electrical Engineering skill and appropriate tools. Tasked with watching the sub's nuclear reactor and maintaining its power levels, as well as repairing the junction boxes and wires that provide power to all compartments. Talents enable Engineers to repurpose the tools of their department for exotic weaponsmithing and the crafting of Depleted Phlebotinum Shells.
  • Mechanic: Starts with the highest Mechanical Engineering skill and appropriate tools. Responsible for maintaining the engines and other mechanical devices, as well as repairing the sub's hull whenever there's a breach. Their talents generally relate to repairwork and crafting, with some bonuses to mining for ore, though one upgrade path gives them a surprising niche as an ad-hoc melee combat specialist.
  • Assistant: The odd one out in that it has no particular focus in any skills and starts fairly low in all of them. They're given far more of a role through the perk system, which lets an Assistant spec into a Master of All who learns skills even faster, a functional Red Shirt who provides benefits to other crewmembers, or a costumed clown who serves as a Quirky Bard.
• Cigarette of Anxiety: Cigars and Captain's Pipes loaded with pipe tobacco can be used to gradually alleviate Psychosis, Hallucinating, Watcher's Gaze and Reaper's Tax.
• Cool Boat: You are the owner of one of several types of subs capable of surviving in the hostile undersea environment of Europa. Each sub has at least some kind of defense against the native life or alien machinery on the moon - electrical discharge coils, depth charge tubes, coilguns for small, numerous foes and railguns for the truly monstrous. The mightiest of the subs are the Kastrull and Typhon 2 which are the heavy gunships of the submarine world. For civilian purposes, the kings of commerce are the Berilia and Remora.
• CPR: Clean, Pretty, Reliable: If a crewmember is suffering from the "low oxygen" affliction, you can use the healing interface to perform CPR on them to alleviate it. However, this is tied to your medical skill — You need at least 50 points in medical skill to actually heal the affliction this way (rather than merely slow it down or stabilize it), while attempting CPR with a medical skill of less than 20 will cause internal damage with each pump.
• Critical Existence Failure: As long as your stamina bar is above zero, you can walk, talk, and do any task you want. As soon as it hits that magic number, though, you'll immediately ragdoll and go unconscious until you're either treated and revived, or die. Somewhat averted in the fact that certain injuries can cause your character to limp, reducing your walking speed.
• Crowbar Combatant: Crowbars are mainly used to force open locked doors and hatches, but can be wielded as basic melee weapons in a pinch. Hardened Crowbars and Demontonite Crowbars are better for both forced entry and melee combat. The Engineer's "Physicist" skilltree, focused around improving nuclear reactor performance, also gives you double damage with crowbars (and increased hazmat suit protection), a clear Shout-Out to Gordon Freeman.
• Cult: Two of them exist on Europa — The Children of the Honkmother, a disorganized movement of Monster Clowns; and the Church of Husk, a transhumanist cult that worships The Virus.
• Deadly Gas:
  • Oxygen and welding fuel use the same type of canister, and a common way to sabotage the submarine is to discreetly replace the oxygen in diving suits and breathing masks with poisonous welding fuel to rapidly suffocate anyone who uses them. (For the reverse, see Explosive Stupidity below.)
  • Ballast flora produces nodes that spew a burning gas to drain the stamina of crewmembers venturing into infested rooms.
  • Underwater caves may contain another type of gas; while not damaging by itself, it will cause your oxygen supplies to drain from your suit. This naturally can result in death if you didn't bring enough oxygen. (Thankfully, oxygen stacking was added in the same update, allowing to bring a surplus)
• Depleted Phlebotinum Shells: Literally, depleted fuel rods can be turned into depleted uranium ammunition and hardened tools by a trained Engineer. Less literally, incendiary explosives and even more powerful Physicorium ammunition for various weapons are made from salvaged alien metals. The unlockable assault rifle and Hand Cannon only fire Physicorium rounds.
• Dirty Bomb: Craftable by Engineers with the right talent. They have much weaker blasts than the true, submarine-launched nuclear weapons, but dirty bombs can be used like explosive compounds: either planted by hand with a detonator or loaded into railgun shells and depth charges.
• Drinking on Duty: Some submarines contain ethanol, which can be a useful crafting ingredient for certain chemicals, but can also be directly ingested, giving 600% resistance to Psychosis for a few seconds (and mildly heals the Psychosis and Hallucinating conditions). This also, predictably, starts inflicting the Drunk and Nausea conditions, decreasing their maximum vitality, movement speed, and distorting their screen. Consuming enough ethanol can actually knock the user unconscious, and even after they recover, their screen will usually be so distorted that it's difficult to actually understand what's going on.
  • Captains can unlock a crafting recipe for Rum by unlocking the "Drunken Sailor" talent, which is crafted using ethanol and raptor bane fruit. It causes a whopping 90 Drunk upon consumption, enough to immediately cripple the drinker's vitality and movement. However, it's also far better at combating Psychosis and Hallucinating than regular ethanol (reducing both conditions by -90), and can even combat husk infection (reducing it by -30). As for the Drunken Sailor talent, it makes Captains immune to the negative effects of being drunk, and gives them 75% stun resistance while drunk.
• Dual Wielding: One-handed weapons such as revolvers can be dual-wielded for double the firepower. Dual-wielding revolvers is actually a good idea in combat because otherwise, unless you get consecutive headshots, most man-sized enemies require the full 6 rounds to put down which means you'll be stuck reloading while being mauled if you miss a shot or two.
• Eldritch Ocean Abyss: The oceans of Europa are lightless voids beneath a nearly impenetrable surface layer of ice, populated by nightmarish aquatic creatures and the remnants of a mysterious alien civilization. Insanity and death are common fates for Europa's submariners.
• Energy Weapon: A pulse laser can be installed as one of the submarine's turret weapons. It hits targets instantly- making it an excellent weapons for bots to man- and deals high heat damage, but requires uncommon materials (alien blood that must be looted from certain creatures, usually requiring trips outside the submarine) to craft. You can also salvage energy-based Alien Pistols and Ancient Weapons from ruins, which run on Alien Power Cells.
• Evilutionary Biologist: The Church of Husk is a transhumanist Cult that believes the husk parasite can be used symbiotically to adapt humanity to Europa. Unfortunately, their efforts to spread "communion" usually involve injecting people with eggs and starting deadly Parasite Zombie outbreaks in colonies or submarines. Downplayed, in that wiser members realize that this isn't a good idea, and have actually developed Husk enhancements that maintain the mind.
• Exact Words: One quest in the Children of the Honkmother questline has a clown asking you to bop an Abyss Creature (the game's boss enemies) with a toy hammer, which is utterly suicidal. However, at no point did he ever say the Abyss Creature had to be alive when you bop it. Killing an Abyss Creature with your sub is still pretty tough, but it's a hell of a lot more manageable than getting out of your sub and interacting with it as a human.
• Explosive Stupidity: Aside from all the interesting ways you can misuse regular explosives, it's possible to accidentally load a welding torch with oxygen or a plasma cutter with welding fuel, causing it to explode in your hand after a short delay.
  • Sodium and potassium, true to life, react explosively to water.
• Expy:
  • The Assistant job, an expendable Redshirt archetype intended for less experienced players, is a direct transplant of the same role from Space Station 13. Not only are their default uniforms near identical, but they also have a talent path called "greyshirt", named for a bit of common playerbase slang.
  • The clowns, famous for being the Series Mascot of SS13. The "Children of the Honkmother" cult references a meme religion sometimes espoused by clown players.
• The Extremist Was Right: While wanting to turn everyone into Husks may sound incredibly stupid, the Church of the Husk actually aren't idiots; their ultimate goal is not to turn into mindless Husk zombies but rather to achieve symbiosis with the parasite and gain its physical advantages without losing their consciousness. They have the means to do this, too, as they sell the equipment needed to genesplice yourself into a sentient Husk, and the robes worn by their leaders have the same effect due to built-in hormone injectors. Unfortunately for them, many of their new recruits are over-eager and fail to grasp the subtleties of all this, and just inject themselves with Husk eggs with no preparation, turning themselves into Husk zombies and starting Husk outbreaks.
• Fantastic Drug: A number of them are available to Medical Doctors, alongside more mundane fare:
  • Calyxanide, which is used to treat husk infection. As a nod to real life toxicology, calyxanide is refined from husk eggs.
  • Deliriumine, a toxin crafted using the anomalous metal "dementonite". It bestows the unique "deliriumine poisoning" affliction, which causes a never-ending uptick of Psychosis until treated with sabilozine or deliriumine antidote.
  • Desuizine, a mix of antibiotic glue, fentanyl and liquid oxygenite. It remedies blood loss, oxygen loss and general damage afflictions, though it inflicts mild burn damage on the patient as a side effect.
  • Hyperzine, a potent cocktail of methamphetamine and anabolic steroids. It grants high amounts of the Hyperactivity and Vigor status effects, and slightly remedies general damage afflictions, low oxygen and stun.
• Final Boss, New Dimension: In the full release of the game, the Eye of Europa is heavily implied to teleport you to the Eye of Jupiter, where you find your sub in an ancient alien ruin where your sub seems to be surrounded by Jupiter's gas instead of water. Here you battle an Ancient Evil Eldritch Abomination named Jove/Yoh-Wey, whose death results in a subsiding of the deadly radiation from Jupiter bombarding Europa, making life much more manageable for the people living there.
• Fluffy Tamer: Assistants can pick up a talent called "The Friends We Made", which enables them to convert mudraptor eggs into "petraptor" eggs using dementonite and a medical fabricator. Unlike their wild cousins, petraptors are fully domesticated, and up to two of them can be kept as crew pets.
• Friendly Zombie: Splicing husk genes into a character makes them unable to be fully huskified, causing husk infection to cap at 90% and preventing reanimation after death. This allows a character to have all the benefits of late-stage husk infection (Super Not-Drowning Skills, immunity to non-Abyss water pressure and healing proboscis attack) without losing control or suffering the deadly seizures that trigger at 100% infection, so long as they don't mind becoming The Speechless.
• Gatling Good: The chaingun can be installed as one of the submarine's turret weapons. It possesses great firerate and DPS, but needs to be spun up to use and eats through ammo reserves way too fast for a game where every ammo crate must count.
• The Gunslinger: The Captain class has a talent path of the same name, which provides bonuses for pistols and revolvers. This path culminates in unlocking a Hand Cannon crafting recipe.
• Hammerspace: The Toolbelt item is a useful piece of gear for any character, basically granting a free extra six inventory slots without needing to be lugged around as a prop. Although it's supposed to be used to store tools for workers, it can also hold multiple shotguns, loaded harpoon guns, and even explosives. Not to mention its extreme utility for doctors, who can use it to store additional medicine items.
  • While it got nerfed in that it can't hold items too large such as shotgun and has only 6 slots, the Toolbelt still can hold full stacks of smaller items. And those items are immune to being detonated by fire, so your oxygen supplies are safe.
  • You can also fill a storage crate with toolbelts, effectively multiplying the number of slots in it. This can be extremely handy when looting a shipwreck, but raises questions about how delivery missions only have up to 20 items in such crate when you can put in 960...
• Hand Cannon: A weapon recipe unlocked by Captains at the end of the Gunslinger talent path. The handcannon and its .61 caliber ammo are crafted from salvaged alien metals, and hit with enough force to stun targets.
• Harpoon Gun: Present as a short-to-medium range weapon, which inflicts lacerations and bleeding. Harpoon guns are equally effective in the water as they are on land, and fired harpoons can be retrieved from the environment, making them a very practical and cost-effective weapon. A harpoon can combined with C4 to craft explosive-tipped harpoons, for extra bleeding and deep tissue injury afflictions.
• Healing Factor: Husks passively heal all damage-related afflictions at a slow rate (usually around 1 point per second), and heal a bit more whenever they land an attack. Fresh husks created from crewmembers are able to eventually heal back to full function when brought to an "unconscious" state from loss of stamina, forcing players to double-tap and make sure they're dead.
• Heal Thyself: Averted. Healing isn't instant, and it isn't easy: you have to diagnose the condition first (either through opening the healing menu or wearing a Health Scanner HUD), and then find and use the appropriate treatment.^note Also, the recommended treatment menu won't be 100% accurate if your Medical skill isn't high enough, but an experienced player can memorize the treatments for each condition, so it's not as bad as it sounds.
• I Need a Freaking Drink: If no haloperidol is available, the Psychosis and Hallucinating ailments can be mildly combated by drinking ethanol, which reduces both by -20.
• It Can Think: Downplayed. Husks are feral zombies, but you'll quickly learn that they're not completely mindless — They can open doors like crewmembers can, so long as they're unwelded and unlocked. Doors locked by clearance level can be opened by husked crewmembers if they're wearing the correct ID card.
• Item Crafting: Tools, components and other supplies can be crafted at a Fabricator by characters with the skill most relevant to each item (Weapons for guns and ammo, Electrical Engineering for wiring components, etc.). Healing items and toxins are instead crafted at a specialized Medical Fabricator. A Deconstructor, meanwhile, can be used to dismantle items into their component parts for re-use. Outposts contain a Fabricator and Deconstructor, allowing players to participate in crafting even when playing with submarines lacking those facilities. There is no such luck with the Medical Fabricator, however – if your sub lacks it, you will have to resort to buying medicine or looting it from wrecks.
• Living Ship: The Rusted Remnants update introduced the thalamus, a parasitic colony organism that infests wrecked submarines to animate as its "body". On top of using the craft's conventional weapons, the thalamus can also use organic growths to fire tethers at other submarines, reeling them in to puncture the hull with a spike that disgorges hostile Mega-Microbes. Players can board the infested sub in an attempt to sabotage its organs, and destroying the thalamus' brain will render the entire craft inert.
  • The legacy version of the game had a creature known as the carrier, a small submarine which has been infested with the husk parasite. Unlike the submarines infested with the thalamus, this one is fully mobile and can attack the player's sub by ramming into it, generally functioning like any other enemy. While it has been cut as of the Steam release, it can still be spawned with console commands and the mission where you encounter it can be modded back in.
• Lovecraft Lite: Hostile Starfish Aliens and cults abound in the Eldritch Ocean Abyss with a deadly radiation making it even more unlivable - but humanity is shown to face it not with madness but grim determination, has developed ways to resist the Jovian radiation, and the ending involves killing the source of the radiation.
• Magikarp Power: The "Among the Ancients" update (October 2021) added the talent tree mechanic, where various jobs can gain exp during every mission to unlock powerful abilities ranging from Damage Reduction to unlocked item recipes, meaning that as a campaign goes on longer the players become inherently more powerful, but the job that was buffed the most was the Assistant, whose talent trees allow it to turn into a Master of All, revive from death, and turn the normally-useless clown into a Lethal Joke Character that can use its bike horn to automatically repair machinery and heal injured crew, turning what was normally a Master of None job into a powerhouse.
• Make It Look Like an Accident:
  • A few missions require you to discretely remove an official at an outpost, either as an assassination or to steal something from their safe. Unless you want to tank your reputation with that faction and shoot your way through the base, you'll need to do it discreetly. Some options include injecting them with poison or even parasite eggs (since injections don't count as a hostile action), or wearing a diving suit, getting them to follow you into your ship's airlock (which they don't have authorization to open/close), locking the doors, then opening the airlock and watching them explode from the deep sea pressure.
  • In Traitor Mode, this is an ideal approach when killing another crewmember appears on the to-do list. With a bit of ingenuity, crewmembers can be killed by washing them out the airlock or trapping them in a room with an angry monster.
• Master of Disguise: If the mechanic is enabled, wearing an ID tag that isn't yours and a mask allows you to assume other players' identity. As long as you don't give away your identity in voice chat, this can aid players who have been picked as a Traitor and been given objectives to sabotage the submarine in any number of ways.
• Meat Moss: Ballast Flora is a plant-like colony organism that can take root within a sub's ballast pumps if it passes through a spore cloud. From there it spreads, overtaking devices and reaching for sources of electricity such as junction boxes or the reactor, which can cause a sub to lose power. Areas infested by the flora quickly become uninhabitable, as specialized growths begin to produce a corrosive gas that rapidly drains health, and it will protect itself by triggering doors and pumps in a further effort to kill the crew. The only way to clear the colony out is to cleanse the ballast pump from which the creature is growing, which can be done with heat-based weapons like welding/cutting tools, incendiary bombs or flamethrowers. Ballast flora allowed to grow in a shipwreck over the course of years eventually forms a thalamus — a hostile Ghost Ship entirely overtaken by the Meat Moss.
• Mega-Microbes: Leucocytes are cell-like creatures spawned by a thalamus, capable of chewing through hulls and inflicting paralysis on humans they attack. When threatened they can also spawn smaller, palette-swapped versions of themselves called "terminal cells", which explode upon death.
• Monster Clown: A carry-over from Space Station 13, clowns are memetically stereotyped as always being up to no good, to the point where there's an achievement for murdering somebody for the crime of wearing a clown costume. They're the remnant of a disastrously misguided attempt by the Europan Coalition to create a morale-boosting entertainer role for their crews, and the deeply disturbed clowns of Europa have since organized themselves into "the Children of the Honkmother". Available to Assistant players in the Clown talent tree is the Psycho Clown talent, which causes the psychosis ailment to also increase the clown's melee attack speed and slow their movement to an Ominous Walk.
• Nemean Skinning: The Mudraptor Armor outerwear, which has a 5% chance to drop from slain mudraptors.
• Non-Ironic Clown: A Clown who actually wants to be helpful can mend machines, boost skills, and even heal wounds with the right talents and a bike horn.
• Optional Party Member: There are a handful of pre-made NPCs that can be recruited into your crew as part of a random quest. Recruiting some of them will even give you an achievement.
• Our Zombies Are Different: Husks are caused by an invasive parasitic infection that gradually sickens and kills the host, before they reanimate into a vicious Parasite Zombie wholly dedicated to infecting or killing the remaining crew. Unlike the stereotypical zombie’s method of transmitting the disease, their methods of infecting other hosts rely on striking them with the stinger protruding from their mouths, which inject the Husk parasite’s eggs into the victim. Unlike other cases which involve a Zombie Infectee, euthanising an infected host will not prevent reanimation and thus they will need to be either contained or shot when they inevitably rise, but the parasite can be cured if the infection is caught early. However, the cures are hard to come by and one needs to be synthesised from the eggs found in the bodies of other Husks.
• Pet Monstrosity: In one quest, a nervous person asks you to transport him to another station. If you agree to transport him, he reveals that he has a pet mudraptor who is easily irritated.
• Powered Armor: Exosuits, unlocked by a late-game Mechanic talent, are hulking suits of armor normally used for construction projects. It boasts built-in toolbelt storage, a headlamp, superior protection against many afflictions, resistance to water currents, and the highest possible resistance to water pressure (-10000 meters, matched only by the Abyss Diving Suit). Wearing an Exosuit also enables the user to fire a Heavy Machine Gun without being knocked down by recoil, even if the user doesn't have sufficient Weapon Skill. The main downsides are that, along with needing an oxygen supply like a standard diving suit, the Exosuit is so outrageously heavy that it needs to be powered by a nuclear fuel rod, otherwise the wearer can't move at all; and even with power, the user's movement speed is drastically reduced even with the aid of a water scooter.
  • Completing the Clown talent path grants Assistants their own exosuit model, the Funbringer 3000, painted in clown red and decorated with a monstrous carnie face. It lacks the extra inventory of the vanilla exosuit, but gains a built-in Banana Peel cannon and a "honker blast" that causes nearby characters to Hallucinate for a few seconds.
    The clowning achievement of Honkmotherian technology: a nuclear-powered exosuit equipped with weapons of mass pranking.
• Pre-Final Boss: At the very end of the game, after entering the Eye of Europa and being transported through space-time, you eventually battle a unique Endworm that's been cybernetically enhanced with alien-material armor and turrets replacing its mandibles. Fortunately, the thing seems ancient and has taken quite a lot of damage over the aeons, including missing one mandible-turret and the rear 1/3rd of its body. It's actually only a prelude to the real Final Boss fight, an Ancient Evil Eldritch Abomination called Jove/Yoh-Wey.
• Raising the Steaks: Husked crawlers can sometimes be encountered, visibly discolored and mutated by the parasite.
• Raptor Attack: Mudraptors are a common enemy that resemble a cross between a dinosaur and a shrimp. They possess armored beaks to break into ship hulls, and powerful hind legs that allow them to walk upright and even run once they get inside.
• Red Shirt: The Assistant's Greyshirt talent tree gives bonuses that help offset the pain of dying (or give ways to improbably survive.) Other classes talents that give rewards for the whole crew surviving often don't count assistant casualties.
• Resurrection Sickness: The affliction "Reaper's Tax", caused by dying and respawning via shuttle, reduces the player's maximum vitality and movement speed, and inflicts a penalty to skill use. According to the medical interface, it's caused by unsettling Past-Life Memories of the character's earlier demise. The only way to cure it is to use a cigar or visit an outpost medical clinic between missions. A Greyshirt Assistant can pick up the talent "An Apple A Day", which confers 100% resistance to gaining Reaper's Tax.
  Examining Others: The patient is tormented by painful visions of death and rebirth. Memories of past lives, or just a stress reaction? Consulting a medical doctor at an outpost is advised.
  Examining Self: You’re plagued by a sense of deja vu, and it’s too real. Maybe you should be glad you can only remember your death, and not your birth.
• Sanity Meter: A downplayed variation exists in the form of the Psychosis ailment, which is contracted when a player handles a Psychosis Artifact or ingests Alien Blood, or too much methamphetamine or anabolic steroids. While not directly hazardous to the victim, if left untreated it causes the player to suffer hallucinations of fire and screen shaking (the latter usually indicating the sub is being struck by big alien fish), making it difficult for them to report genuine emergencies. This has to be treated with Haloperidol if the ailing player is to continue being an effective crew member.
• Seal the Breach: A common and serious issue that needs to be addressed by someone with a welder. The hull can crack with damage, causing compartments to flood and requiring the one responsible for sealing it to wear a rebreather. Larger breaches open the hull to the ocean, which requires a full diving suit to withstand the water pressure long enough to repair, and may potentially expose the crew to monsters entering the ship.
• Sci-Fi Horror: Humanity has achieved space flight, but Europa can't be colonized on the surface, so they went underwater instead. Naturally this means dealing with the omnipresent hazards of the Europan xenobiology, and more chillingly, the human element.
• Silent Running Mode: The submarine's sonar will reveal the rough shape of lifeforms and terrain for some distance around the craft, but can allow hostile creatures to home in on its location. To alleviate this, the sonar can be set to a minimal "passive" mode that hides the sub's presence somewhat, but forces the navigator to fly blind or rely on autopilot. The sonar can also send out directional pings, which highlight shapes in a narrow cone.
• Shout-Out:
  • There's a Security Officer talent named Inordinate Exsanguination, out of a narration line from Darkest Dungeon.
  • The Physicist talent line for Engineers culminates in "PH.D in Nuclear Physics", which boosts crowbar damage and unlocks a special yellow-orange diving suit (the PCUS) which improves radiation resistance and has a medicine autoinjector. All in reference to Gordon Freeman and his HEV suit.
  • One of the Assistant talent paths is "Greyshirt", simultaneously referencing Star Trek and Space Station 13^* Where "greyshirt" is an informal playerbase nickname for the assistant class, which Barotrauma's Assistant is an Expy of.
• Social Deduction Game: The optional Traitor Mode gives a random member of the crew a list of secret tasks to perform during the current deployment, which usually involve sabotaging the sub or killing other crewmembers while avoiding suspicion. The traitor "wins" if they can complete their objectives before the mission ends, netting them various rewards (like stealing a chunk of everyone's mission XP). The rest of the crew get to vote on who the traitor is over the course of the mission, tallied at the end of the round. If at least half the crew vote correctly, it aborts the traitor's mission (or invalidates their reward if they'd already finished), but failure causes the whole crew to suffer a monetary penalty.
• Spike Shooter: The Spineling is an agile swimming creature and one of the few creatures in the game with a ranged attack — it fires its namesake spines like harpoons, with enough force to puncture multiple decks of a submarine. A regular spineling is small enough that its barbs only cause minor leaks, but it has a much larger relative, the Giant Spineling, that fires barbs bigger than the humans they skewer.
• Static Stun Gun: The appropriately named stun gun is a pistol which fires electric darts, causing targets to ragdoll helplessly for ten seconds. The stun baton, meanwhile, is a battery-powered melee weapon that can ragdoll targets for up to ten seconds after several hits (3 on Normal battery, 2 on fulgurium one). Stunning weapons are the typical first resort against rowdy members of the crew, with the stun state being used to quickly slap handcuffs on the offender.
• Submarine Pirates: Separatist submarines will engage in piracy against Coalition transports, and Coalition outpost leaders will occasionally give you missions to hunt and destroy said subs. Unaffiliated pirates will also occasionally take over beacon stations and outposts, and will have to be cleared out before you can reclaim the buildings.
• Sub Story: With a Sci-Fi Horror twist. Aside from brief visits to outposts and the occasional EVA jaunt in a diving suit, the entire game takes place within the cramped confines of a player-operated submarine.
• Super-Strength: Possible by consuming anabolic steroids, this makes a player able to do more melee damage and even resist trauma in close quarters.
• Through the Eyes of Madness: The Psychosis affliction causes the player to randomly hallucinate sounds and visuals, including gunshots, alarms, monster calls, broken devices, screen quaking, ship impacts, fires and floods. More dangerously, Psychosis can sometimes conceal existing characters and floods, further inhibiting your ability to respond to genuine threats. In addition, Psychosis is impossible to self-diagnose using the medical interface, so you might not realize you've been hallucinating at all until a medically trained fellow crewmember checks you out.
• Underwater City: Although perhaps not as large and sprawling as this trope would suggest, populations usually numbering at a dozen or so, the campaign mode features outposts you can travel to and rest at, where you can search for jobs, hire crew members, and buy supplies, submarines, and upgrades for those submarines.
• Underwater Ruins: Alien ruins can be found embedded into Europa's icy walls, with one mission type requiring players to venture into these ruins in order to salvage an Ancient Artifact.
• Unintentionally Unwinnable:
  • During the Mechanic tutorial in v.0.10.5.1, when prompted to fix a major leak that has flooded a room (and requires a diving suit), the player can, under certain circumstances, be sucked through the leak into the open water. If the player is sucked through the hole in the ship while patching up the leak, they will repair the seal completely while also blocking themselves from that area. Because there is no door to the top half of the tutorial area, the player can only enter the submarine underneath - and because the hatch separating the submarine and the main ship is unopenable (the game will say that the player has "unauthorized access"), the player cannot get back into the main area, and thus cannot complete the tutorial, forcing them to restart.
  • Another variation occurs if the player knowingly seals the only entryway after being forced into the open water, instead of swimming back through it; the tutorial becomes unfinishable either way.
• Variable Mix: The game's music will change depending on context, such as a creature being nearby, your submarine sinking, and so forth.
• Video Game Cruelty Potential: If you want, you can certainly go Ax-Crazy on your fellow crewmates, taking a weapon and bludgeoning their skull, or shooting them until they drop. Do this at your own risk: some servers will ban you for this, and other crew members can (and likely will) fight back.
  • Server owners can also turn a feature called Traitors on to give random crew-members tasks to do, usually with the goal of either sabotaging the submarine or killing off some of the crew.
  • If you're unlucky enough to become a Zombie Infectee and can't get cured in time, you'll eventually develop a proboscis in your mouth that can be used to infect other players. Since you'll eventually die and become an AI-controlled zombie no matter what, the ability to use the proboscis manually is this trope mixed with dying spite.
• The Virus: Husks are former humans and crawlers with a tentacle sticking out their mouths, plagued by what's simply known by the shorthand "husk infection". The only two ways to contract this are for human players to get attacked by the proboscis of Husk enemies, or for somebody (likely a traitor) injecting dormant eggs into them. The symptoms are invisible to anyone not wearing health scanner goggles, and as the infection progresses the victim eventually loses the ability to chat, and if left untreated the player will succumb and upon death will resurrect as an AI-controlled husk that must be put down again. As a reference to real life toxicology, medics need to loot husk eggs from NPC husks as part of making calyxanide, the one of two only medicine items able to treat the infection in its early stages. If the infection is left to fester to completion, the aforementioned cures will kill the victim.
• Weld the Lock: The welding tool can be used to seal a door shut, forcing monsters to tear it down and players to slice it open with a plasma cutter.
• With Friends Like These...: Par for the course when joining random games. You can never be sure if you'll get a serious crew or any number of clowns (you can literally dress as one) who will eagerly place an oxygen tank in a welding tool then fire it near the oxygen tanks to cause a suicide explosion that will absolutely wreck weaker subs. Or raid the armory for weapons and start gunning down everyone in sight.
• When All You Have Is a Hammer…: The welding tool, plasma cutter and wrench can be used as very weak weapons in a pinch, and actually managing to kill something with any of them is a Steam achievement titled "Whatever works".
• Wrench Whack: Wrenches can be used as crude melee weapons, and the Mechanic class can take a perk that gives their wrenches 30% chance to deal double damage on a hit, as well as being more likely to stun a target.
• You Nuke 'Em: With the right materials, players can craft nuclear railgun shells, nuclear depth charges, or dirty bombs. All unleash deadly radiation, and the blast radius of nuclear ship munitions makes them difficult to use without harming one's own submarine and crew. However, they are the most powerful weapons available; a good shot can destroy a pirate submarine or thalamus wreck with a single nuke shell.
• Zombie Infectee: Players can contract the "husk infection" affliction from husk attacks, which slowly ticks upwards to 100%. If not cured, the husk parasite will progressively spread throughout the body, eventually robbing the player of the ability to speak or use commands and signals. At the penultimate stage of the infection, the player gains the abilities of husk zombies, including Super Not-Drowning Skills and an infectious proboscis in their throat — though it's only a matter of minutes before they're stricken with deadly seizures and expire, as the parasite takes full control. Be warned that simply executing an infected player won't prevent their corpse from reanimating.
  • The "Cultist Transport" mission involves ferrying a group of acolytes from the Church of Husk to the next station over. Unfortunately, at least one acolyte in the group is attempting an unsanctioned "communion" with the husk parasite, endangering the crew and other passengers unless they're discovered and cured in time.

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