Brotula game

Brotula game is a roguelike about a deep immersion to the very sources of life and water. Battles are turn-based and are fought as a duel of brain cells: each side fills a 3×3 grid with skills that real deep-sea animals use, and the side that extinguishes more enemy cells wins.

Developer: Octanta Studio (Ukraine)
Engine: Unity
Genre: roguelike, turn-based tactics
Languages: English, Ukrainian
Platforms: mobile devices, and in the browser on PC
Release: first released on mobile in August 2022; published on itch.io in 2026
Game page: https://octantastudio.itch.io/brotula
Studio website: https://www.octantastudio.com/
Author: Dariia Zodcha (Octanta Studio). Everything from the art to the code was made by hand
Music and sound: Shvetsb

World and story

The world of Brotula is the ocean seen as the memory of water. The game is a deep immersion to the very sources of life and water: not a plain trip to the bottom and not a decay, but a way back toward the origin.

The explorer

The player controls a sexless deep-sea explorer. The explorer keeps dying and is replaced by a modified one, so memory is erased between dives. After a death the player lands on the capsule screen, sets up genes and starts a new expedition.

Water memories

Water is one and remembers everything, so it acts as the carrier of the memory that the explorers lose. Water memories drop at random as battle rewards. Each one shows a picture and a text and opens the next scene of a story, in order.

The story is the backstory of the explorer. A man tests Brotula, the first social network built into human consciousness, and watches people around him dissolve into it. Tired of the high-tech world, he leaves, joins the deep-sea expeditions and becomes an explorer like the one the player controls.

Zones

The zones are part of the lore. Their names appear on the screen as the dive goes deeper (depth in metres, as shown in the game). Different creatures and mermaids appear in each zone (see creatures).

Zone	Name appears at
Abyssal zone	5150
Hydrothermal vents	5650
Hadal zone	6700
Trench	8520
Trench bottom	10550
Subduction zone	12150

The goal

The aim of the game is to reach the lowest secret biome and find ringwoodite crystals, the first structures that formed water on Earth. The biome is left as a mystery: its visuals and music differ from the rest of the game, and its gameplay is slightly different.

Look

The visual style is monochrome black and white with red. Both the explorer and the creatures can be any colour in that range.

How a run works

Before the dive the player chooses genes. Genes progress globally between dives, and each gene has levels from 0 to 3. Up to 4 genes can be inserted before an expedition, or 5 with the Intensive development gene.
The dive. The player holds the bottom of the screen to swim down through biomes. Depth is shown in metres. Zone names appear on the way: Abyssal zone, Hydrothermal vents, Hadal zone, Trench, Trench bottom, Subduction zone. Each zone has its own creatures and mermaids.
Skills. Skills are learned during the dive for caviar. Caviar is food: it gives energy, and energy is spent on training a skill. Skills exist for one dive only.
Encounter. The player swims until a creature blocks the way. Its brain cells are already filled with the skills it will use. Before the fight the player can inspect them (a tap on an enemy skill shows its targets) and set up a formation in response. New skills cannot be learned at this point.
Start or flee. Tapping the enemy starts the fight. Tapping your own creature is an attempt to escape, and escape is a chance, not a guarantee.
Battle. See mechanics/battle.md.
Reward. After a victory the player picks one reward: caviar, a companion (mermaid) or a water memory.
Level-ups. Battles give experience. Each new level offers a choice between two permanent rewards: +1 to the initial caviar stock (it starts at 9) or +1 companion slot (the slots start at 2 and stop at 6). Once all 6 slots are open, only the caviar reward is offered.
Companions. Between fights the player can spend time with a mermaid. After the next fight she generates genes that she can produce, the player picks among them, and the chosen genes are injected after the dive.
Defeat. The first defeat in a dive can be survived, and the player swims on. When the explorer dies, the player is thrown to the capsule screen, where genes are set up between dives, and then starts a new expedition.

Progression

Carries over between dives: genes and their levels, the player’s level, the initial caviar stock (it starts at 9) and the number of companion slots (2 at the start, 6 at most).
Lasts for one dive only: skills. They cost 1 to 5 caviar each.

Battle

A battle in Brotula is a turn-based duel between two sets of brain cells. The player and the creature each fill a 3×3 grid with skills, the two sides take steps in turn, and the side that extinguishes more enemy cells by the end wins.

Brain-cell grids

Each side has a grid of nine brain cells.
A cell that holds a skill is a unit with 1 HP. An empty cell holds no skill, takes no damage and counts as a skipped step.
A cell that is damaged is extinguished and stays extinguished until the end of the battle.
Every extinguished enemy cell adds 1 to the player’s total damage, and every extinguished cell of the player adds 1 to the enemy’s.
The goal is to extinguish more enemy cells while losing as few of your own as possible. Whoever extinguished more enemy cells by the end of the battle wins.
In battle both creatures shift to the left of the screen. The player’s grid opens on top, the enemy’s grid opens below it.

Before the fight

The player swims down until a creature blocks the way.
The creature’s cells are already filled with the skills it will use.
The player may inspect them: a tap on an enemy skill shows its targets.
The player sets up a formation in response, by tapping their own skills or through the brain button at the top of the screen, which opens the player’s skills.
New skills cannot be learned at this stage. Preparation had to happen earlier in the dive.
Tapping the enemy starts the fight. Tapping your own creature tries to escape (see Escape).

The formation has to be set before the fight starts.

Turn order

The two sides take steps in turn. A round has 18 steps: 9 for the player’s cells and 9 for the enemy’s.

The player moves first. Player steps run from the bottom-right cell of the player’s grid to the left, then up row by row. Enemy steps run from the top-right cell of the enemy’s grid to the left, then down row by row.

Player’s grid (top):

17	15	13
11	9	7
5	3	1

Enemy’s grid (bottom):

6	4	2
12	10	8
18	16	14

The enemy moves first. The order is mirrored: the enemy takes steps 1, 3, 5 and so on, the player takes steps 2, 4, 6 and so on.

Player’s grid (top):

18	16	14
12	10	8
6	4	2

Enemy’s grid (bottom):

5	3	1
11	9	7
17	15	13

Skill effects

Every skill carries one or more icons. The in-game hint (opened by tapping the red starfish at the top right of the skills screen) explains each one.

Icon	In-game description
fish with a mouth	Lowers enemy brain cell activity (attack -1)
heart in a tentacle	Increases brain cell activity (heal +1)
closed mollusc	Clouds the mind while not extinguished (permanent block)
open mollusc with a stone between the valves	Maintains mental clarity while not extinguished (permanent antiblock)
sea cucumber (holothurian), stylized	The cell generates a long-lasting impulse (effect x3). These are the poison skills
cave with a lurking creature	The cell is activated and damaged when excited (trap -1)
neural connections	Impulse reaches multiple targets. Put on every skill with more than one target

A skill with several effects shows several icons, for example an attack with many targets shows the fish and the neural connections.

Targets and markers

A red crosshair on the enemy’s grid shows where the selected skill hits.
A white crosshair on the player’s own grid shows the target of a skill aimed at the player’s own cells, for example A breath of calm.
A white outline on the player’s own grid shows the cells where the selected skill can be placed.

High pressure

With depth, pressure closes the cells of both grids. A closed cell is blackened: it is invisible on the enemy’s grid and cannot be occupied on the player’s grid. Cells 1, 2 and 3 never close. Cells 4 to 9 close at the depths below (metres, as shown in the game). Enemy cells close at the same depths.

Cell	Closes at	Closes at, with partial protection	Gene that protects it
9	5600	6300	Lipids
8	6000	8000	Gigantism
7	6300	8470	Hydropores
6	6650	9000	Hard body covering
5	6800	9500	Statoliths
4	7000	10000	Gelatinity

A gene at level 3 keeps its cell open for the whole dive. A gene at level 2 gives a chance to delay the closing to the deeper depth. Level 1 has no effect on pressure. In the Subduction zone (below 12030) the closed cells of enemies are reopened.

Escape

Tapping your own creature before the fight tries to escape. Escape is a chance, not a guarantee. The Mimicry gene at levels 2 and 3 improves the chance. According to the game scripts, creatures of the fish type cannot be escaped from, and escape is also disabled in the deepest part of the Subduction zone.

Reward

After a victory the player chooses one reward: caviar, a companion (mermaid) or a water memory.

Caviar is food. It gives energy, and energy is spent on training new skills during the dive.
A mermaid takes one of the companion slots. There are 2 slots at the start and up to 6. See companions.
A water memory shows a picture and text and unlocks a story scene. Memories drop at random.

Level-ups

Battles give experience. Every new level shows the message “Level N reached!” and the player chooses a permanent reward: +1 to the initial caviar stock (the stock starts at 9) or +1 companion slot (2 at the start, 6 at most). With all 6 slots open, only the caviar reward is offered.

Skills

A skill in Brotula is an action that the player places on a brain cell before a battle. It is one of the moves that real deep-sea animals use to hunt, defend themselves or hide. A skill lasts for one dive.

The icons that mark effect types are described in the Skill effects part of the Battle section.

How skills are obtained

Skills are learned during the dive for caviar. Caviar is food: it gives energy, and energy is spent on training a skill.
New skills cannot be learned once the player has met a creature and the battle is being prepared.
Skills 1 to 9 need no genes.
Every other skill unlocks only when the listed gene reaches level 3 (the maximum). Skills 30 to 43 need two genes at level 3.

All skills

ID	Skill	Caviar	Effects	Genes needed (level 3)
1	Silent threat	1	attack	none
2	Aiming to hit	1	attack	none
3	Flick	1	attack	none
4	Distraction bait	1	block	none
5	Vigilance	2	antiblock	none
6	A breath of calm	2	heal	none
8	Dream of life	2	heal	none
9	Hypnotic dance	1	block	none
10	Competence in anatomy	2	heal, multi-target	Red pigmentation
11	Comprehensive recovery	2	heal, multi-target	Red pigmentation
12	Invisibility	2	antiblock	Transparency
13	A weak point detection	1	attack	Black pigmentation
14	Merging with darkness	1	attack	Black pigmentation
15	Blinding camouflage	1	block	Bioluminescence
16	Puncture	4	attack, multi-target	Cirri, needles
17	Pinch	4	attack, multi-target	Pedicellariae
18	Bacteria cleansing	3	heal, multi-target	Pedicellariae
19	Tentacle tenacity	3	block	Tentacles, suckers
20	Autotomy	3	trap	Regeneration
21	Bite	5	attack, multi-target	Teeth
22	Thanatosis	3	attack, block	Evisceration
23	Ink cloud	4	attack, multi-target	Ink bag
24	Ink jet	4	block, multi-target	Ink bag
25	Improvised bandage	4	heal	Cuvier tubules
26	Improvised bandage	4	heal	Cuvier tubules
27	Sticky touch	4	block, multi-target	Colloblasts
28	Poison touch	5	attack, long-lasting	Toxins
29	Silt coating	3	antiblock, multi-target	Fins
30	Jaw ejection	4	attack, multi-target	Teeth + Evisceration
31	Poison bite	5	attack, long-lasting	Teeth + Toxins
32	Eerie shouting	4	attack, multi-target	Mechanoreception + Evisceration
33	Body bloat	5	attack, multi-target	Gigantism + Fins
34	Improvised lasso	5	attack, multi-target	Colloblasts + Cuvier tubules
35	Wound healing	5	heal, multi-target	Colloblasts + High immunity
36	The secret of longevity	5	heal, multi-target	Red pigmentation + High immunity
37	Distracting dance	4	block, multi-target	Pheromones + Bioluminescence
38	Fast flashing	4	block	Gelatinity, mucus + Bioluminescence
39	Counter-illumination	4	antiblock, multi-target	Transparency + Bioluminescence
40	Disorientation	5	attack, multi-target	Black pigmentation + Ink bag
41	Blind needle attacks	4	trap	Cirri, needles + Regeneration
42	Scary camouflage	5	heal, block	Tentacles, suckers + Mimicry
43	Pulling pincers out	5	attack, block	Pedicellariae + Intensive development

Skill notes

A skill that combines effects carries several icons, for example Thanatosis is both an attack and a block.
The ID is the skill’s internal number in the game. The numbering has no skill 7.
Skills 25 and 26 share the name Improvised bandage.

Genes

A gene in Brotula is a permanent upgrade of the explorer. Genes are the global progression of the game: skills last for one dive, genes carry over between dives. There are 35 genes, and each one has levels from 0 to 3.

How genes are obtained and used

Companions (mermaids) generate genes. A mermaid chosen for time between fights produces genes of her own type after the next fight, and the player picks among them. See companions (planned).
Genes found during a dive are collected and injected after the dive, before the next one. The gene screen groups them as new available genes, new inserted genes and degrading genes.
Up to 4 genes can be inserted before an expedition, or 5 with the Intensive development gene.
Level 3 is the maximum. Many skills unlock only at level 3 (see skills).

Genes that open cells under high pressure

At depth, pressure closes cells 4 to 9 of the player’s grid. Each of these genes keeps one cell open. At level 3 the cell stays open for the whole dive, at level 2 there is a chance to delay its closing, and level 1 has no effect on pressure. Depths are in battle mechanics.

Gene	Cell	In-game explanation
Gelatinity, mucus	4	amorphousness and secretion increase body maneuverability and equalize pressure
Statoliths	5	these organelles help maintain balance and steadiness
Hard body covering	6	scales or shell protect the body from deformation, but impair its streamlining
Hydropores	7	a special water filtration system equalizes internal and external pressure
Gigantism	8	the larger the organism, the longer it keeps warm and the slower it functions
Lipids	9	a fat-filled swim bladder provides buoyancy but reduces the echolocation ability

Two pairs work against each other. Lipids at levels 2 and 3 only work while Echolocation is lower. Gelatinity and Hard body covering cannot both be at full strength.

Genes that reveal the enemy’s cells

Under pressure the enemy’s cells are blackened and invisible. Each of these genes keeps one enemy cell visible. The levels work like the pressure genes above.

Gene	Enemy cell	In-game explanation
Chemoreception	4	substance concentration changes are more tangible
Photoreception	5	light and its polarization are more tangible
Mechanoreception	6	wave oscillation is more tangible
Thermoreception	7	temperature changes are more tangible
Osmoreception	8	pressure changes no longer cause perceptual disturbances or destroy proteins
Magnetoreception	9	the Earth’s magnetic field is more tangible

Genes that unlock skill families

Each gene below names a family of skills it makes available. The skill list is in skills.

Gene	Skill family	Skills opened alone	Skills opened together with another gene
Red pigmentation	healing skills	10, 11	36 (with High immunity)
Transparency	defensive skills	12	39 (with Bioluminescence)
Black pigmentation	offensive skills	13, 14	40 (with Ink bag)
Bioluminescence	blocking skills	15	37 (Pheromones), 38 (Gelatinity), 39 (Transparency)
Cirri, needles	ranged skills	16	41 (with Regeneration)
Pedicellariae	melee skills	17, 18	43 (with Intensive development)
Tentacles, suckers	skills from the middle row	19	42 (with Mimicry)
Regeneration	health-threatening skills	20	41 (with Cirri, needles)
Teeth	power absorption skills	21	30 (Evisceration), 31 (Toxins)
Evisceration	skills used a limited number of times	22	30 (Teeth), 32 (Mechanoreception)
Ink bag	mass destruction skills	23, 24	40 (with Black pigmentation)
Cuvier tubules	point-focused skills	25, 26	34 (with Colloblasts)
Colloblasts	skills for which targets are chosen in groups	27	34 (Cuvier tubules), 35 (High immunity)
Toxins	multi-turn skills	28	31 (with Teeth)
Fins	dual skills	29	33 (with Gigantism)

Mechanoreception, Gigantism, Gelatinity, Pheromones, Mimicry, High immunity and Intensive development also take part in two-gene skills, as listed above.

Genes that change the dive

Gene	Effect
Mimicry	the chance to escape from a fight is doubled (levels 2 and 3 improve it)
Echolocation	more creatures are found in biomes: a fat-free swim bladder allows the explorer to make sounds and find objects reflecting them
Electroreception	attracting one new companion during an escape is possible, with mucus needed as a conductor of electrical impulses
Additional fat pad	more energy to make the first move constantly, and a slightly faster dive (levels 2 and 3 add speed)
Additional cavity	companion caviar loot is increased, but the special reservoir is also suitable for parasitic bacteria
Pheromones	the player can spend time with more companions: level 2 allows 2, level 3 allows 3
High immunity	protection from defective genes transferred from companions: granulocytes protect the body from poisons, parasites and diseases
Intensive development	up to 5 genes can be inserted before the expedition instead of 4
Transparency	also adds a small bonus to the chance to escape at level 2 and above

Reduction

Reduction is the name of a degrading state in the gene screen. Its in-game text says that a random gene can be reduced during the next expedition. High immunity protects against defective genes that come from companions.

Full list

Gelatinity, mucus; Statoliths; Hard body covering; Hydropores; Gigantism; Lipids; Chemoreception; Photoreception; Mechanoreception; Thermoreception; Osmoreception; Magnetoreception; Echolocation; Electroreception; Red pigmentation; Transparency; Black pigmentation; Bioluminescence; Mimicry; Toxins; Regeneration; Evisceration; Pedicellariae; Tentacles, suckers; Ink bag; Cuvier tubules; Colloblasts; Cirri, needles; Fins; Teeth; High immunity; Additional cavity; Additional fat pad; Pheromones; Intensive development.

Companions

A companion in Brotula is a mermaid: a female-shaped creature built on a real deep-sea organism. Companions are one of the rewards after a won battle, and they are the source of the genes that the explorer collects during a dive.

How companions work

After a victory the player may choose a companion as the reward. The player chooses among the companions on the screen. The number of companion slots starts at 2 and grows up to 6: each level-up offers +1 slot as one of two permanent rewards (the other is +1 to the initial caviar stock).
Between fights the player opens the companions screen, swipes through them one by one downward and chooses one to spend time with. The player gives her a flower of the deep-sea lily. This is courting that doubles as a study of her anatomy.
The player lives through one more battle and returns to the companions screen. The companion that was chosen generates the genes she is able to produce, and the player picks among them.
Genes are collected during the dive and injected after it, before the next dive. See genes.

What each companion generates

Every companion has her own pool of genes, tied to the organism she is built on. A shrimp-inspired companion can generate a gene of a carapace, a sponge-inspired one generates other genes. A gene marked “x2” or “x3” is more likely to appear than the others in that pool.

Some genes in the pools are defective. Reduction is a degrading gene: its in-game text says that a random gene can be reduced during the next expedition. The High immunity gene protects against defective genes that come from companions.

Related genes that change how companions work:

Pheromones: the player can spend time with more companions (2 at level 2, 3 at level 3).
Additional cavity: companion caviar loot is increased.
Electroreception: attracting one new companion during an escape is possible.

All companions

The first column is the companion’s name in the game. The second column is the in-game description of the organism that inspired her. The third column is the genes she can generate.

Companion	Inspired by	Genes she can generate
Creedeia	Shrimps of the genus Galatheacaris produce a lot of caviar.	Chemoreception, Cirri, needles, Gigantism, Hard body covering, Mechanoreception, Pedicellariae, Red pigmentation
Batizza	Bathysaurus rarely rich this depth. Their oral cavities are full of teeth and liver is lipid-rich.	Additional fat pad x3, Lipids x3, Chemoreception, Hard body covering, Mechanoreception, Teeth
Cirrata	There are many red gelatinous finned octopuses in the depths.	Bioluminescence, Chemoreception, Cirri, needles, Fins, Mechanoreception, Photoreception, Red pigmentation, Tentacles, suckers
Gasta	Fangtooth has an intimidating appearance. Coloring – jet black.	Black pigmentation x2, Osmoreception x2, Teeth
Pharn	Black pelican eels use special pheromones to attract prey.	Black pigmentation x3, Pheromones x3, Additional cavity, Bioluminescence, Chemoreception, Mechanoreception, Reduction, Teeth, Toxins
Nass	Faceless eels can sense the Earth’s magnetic poles, but they are blind.	Magnetoreception x3, Chemoreception, Fins, Hard body covering, Reduction, Transparency
Nemina	Incredibly slippery nemertean worms often become symbionts.	Chemoreception, Cirri, needles, Gelatinity, mucus, Red pigmentation, Statoliths, Toxins, Transparency
Freya	Starfish maintain water-electrolyte balance through pores and regenerate quickly.	Evisceration x4, Hydropores x4, Chemoreception, Pedicellariae, Red pigmentation, Regeneration, Tentacles, suckers, Toxins
Cella	Gatherings of giant amphipods can be found in oases of hydrothermal vents.	Additional cavity, Chemoreception, Gigantism, Mechanoreception, Pedicellariae, Reduction, Statoliths
Pacifica	Brittle stars have strong immunity and a developed regeneration ability.	Evisceration x5, High immunity x5, Hydropores x5, Additional cavity, Bioluminescence, Mechanoreception, Photoreception, Red pigmentation, Regeneration, Tentacles, suckers, Toxins
Abbet	Bathypterois can walk on mud using long pointed beams, and is able to use echolocation.	Echolocation x3, Chemoreception, Cirri, needles, Fins, Reduction
Kophoba	Umbellula sea feathers shine harmlessly at the bottom of the ocean.	Bioluminescence, Mechanoreception, Red pigmentation, Tentacles, suckers
Valva	Sea sponges are a haven for small fish and other creatures.	Cirri, needles, High immunity, Photoreception, Regeneration, Toxins
Vinella	Slimy Pompeian worms can withstand temperatures up to 80 degrees.	Chemoreception, Gelatinity, mucus, Mechanoreception, Photoreception, Regeneration, Statoliths, Tentacles, suckers, Thermoreception
Topel	Giant deep-sea snails from hydrothermal vents are sensitive to Earth’s magnetic poles.	Magnetoreception x3, Additional cavity, Gelatinity, mucus, Hard body covering, Mechanoreception, Statoliths, Tentacles, suckers, Thermoreception
Robins	Predatory cutthroat eels feed on fish, cephalopods and crustaceans.	Magnetoreception x3, Fins, Gelatinity, mucus, Photoreception, Teeth, Toxins
Duse	Giant red scyphomedusa are one of the largest invertebrates predators on the planet.	High immunity x4, Bioluminescence, Chemoreception, Gelatinity, mucus, Gigantism, Mechanoreception, Photoreception, Red pigmentation, Statoliths, Tentacles, suckers
Sactine	The glass sponges of Hexactinellida are often inhabited by commensals and symbionts like shrimps.	Intensive development x3, Osmoreception x3, Chemoreception, Mechanoreception, Reduction, Thermoreception
Chita	Chiton mollusks have a durable shell, but poorly developed sense organs.	Chemoreception, Hard body covering, Mechanoreception, Photoreception, Red pigmentation, Reduction
Kevia	Cusk eels are the most common fish in the hostile deep sea environment.	Magnetoreception x3, Chemoreception, Fins, Hard body covering, Mechanoreception, Reduction, Teeth
Echina	Red sea urchins are centenarians and have many adaptations to depth.	Cirri, needles, Hard body covering, High immunity, Mechanoreception, Pedicellariae, Photoreception, Red pigmentation, Statoliths, Teeth, Tentacles, suckers
Phanosa	Black corals are attractive, but covered in thorns. They grow for hundreds years.	Black pigmentation x3, Cirri, needles, Gelatinity, mucus, Pedicellariae, Red pigmentation, Tentacles, suckers
Theusa	Grimpoteutis octopuses have additional fins and are able to mimic.	Mimicry x4, Additional cavity, Chemoreception, Fins, Gelatinity, mucus, Hard body covering, Mechanoreception, Photoreception, Red pigmentation, Tentacles, suckers
Vita	Vitjazema worms, covered with mucus and sensitive cilia, can shed their proboscis and regenerate.	Evisceration x3, Gelatinity, mucus, Mechanoreception, Red pigmentation, Regeneration
Nadine	Grenadiers prefer hydrothermal vents. Their receptors are highly developed, electrical too.	Electroreception x5, Bioluminescence, Chemoreception, Fins, Hard body covering, Mechanoreception, Photoreception, Teeth
Mikta	Holcomycteronus eels lay a lot of caviar. their eyes are vestigial.	Chemoreception, Fins, Hard body covering, Mechanoreception, Reduction, Teeth
Badge	Some ctenophores have an ink bag and the ability to squirt out a sticky secret.	Colloblasts x5, Ink bag x5, Chemoreception, Gelatinity, mucus, Mechanoreception, Red pigmentation, Reduction, Regeneration, Statoliths, Tentacles, suckers
Vanada	Ascidias develop quickly. High levels of vanadium in the blood protects them from predators.	Intensive development x4, Additional cavity, Hard body covering, High immunity, Red pigmentation, Regeneration, Statoliths, Toxins
Thara	The deepest red hydroid form has been found below 10,000 m. These predators hunt alone.	Gelatinity, mucus, Red pigmentation, Statoliths, Tentacles, suckers, Toxins, Transparency
Amblyss	Sea slugs lack scales and vision, but have improved osmoreception.	Osmoreception x4, Fins, Gelatinity, mucus, Gigantism, Reduction, Transparency
Amblyss	Sea slugs lack scales and vision, but have improved osmoreception.	Osmoreception x4, Fins, Gelatinity, mucus, Gigantism, Reduction, Transparency
Hio	Echiodon pearlfish usually parasitize sponges or holothurians.	Chemoreception, Fins, Gelatinity, mucus, Mechanoreception, Photoreception, Teeth
Galana	Galanteids are sedentary, regenerate quickly and adapt to any depth.	Hard body covering, Photoreception, Red pigmentation, Regeneration, Statoliths, Tentacles, suckers, Toxins
Haala	The pelvic fins of an abyssobrotula are sensory organs. These slender eels lay a lot of caviar.	Fins, Intensive development, Mechanoreception, Reduction, Teeth
Marida	Scyphozoa have more developed sense organs than Hydrozoa and are capable of bioluminescence.	Bioluminescence, Chemoreception, Gelatinity, mucus, Mechanoreception, Photoreception, Red pigmentation, Statoliths, Tentacles, suckers, Toxins, Transparency
Lanta	In Brachiopods, all organs are simplified. They are one of the most ancient creatures on Earth.	Hard body covering, Reduction, Statoliths, Tentacles, suckers
Reeda	Solenogastres do not have a shell, unlike other mollusks.	Chemoreception, Gelatinity, mucus, Statoliths
Mariusa	Unicellular xenophyophores are immune to poisons and can be found at any depth.	Additional cavity, Gigantism, Intensive development, Reduction, Toxins
Celeesi	Polychaete worms have transparent, segmented body covered with sensitive bristles.	Gelatinity, mucus, Mechanoreception, Photoreception, Regeneration, Statoliths, Tentacles, suckers, Transparency
Thanaida	Tiny tanidaceans use pincers to dig holes in the mud.	Hard body covering, Mechanoreception, Pedicellariae, Photoreception
Dellia	Aluminum shell protects giant amphipods from high pressure.	Gigantism, Hard body covering, Mechanoreception, Photoreception, Statoliths
Demosa	Nematodes are ubiquitous. Some species are capable of releasing pheromones.	Pheromones x3, Chemoreception, Gelatinity, mucus, Mechanoreception, Thermoreception
Nirel	Giant isopods Janiridae feed on shrimps and holothurians.	Additional cavity, Gigantism, Hard body covering, Mechanoreception, Photoreception, Red pigmentation
Goloriia	Holothurians are capable of throwing out organs or toxic cuvier tubes for self-defense.	Cuvier tubules x5, Black pigmentation x4, Evisceration x4, Additional cavity, Cirri, needles, Photoreception, Red pigmentation, Regeneration, Statoliths, Tentacles, suckers, Toxins

Companion notes

There are 44 companions with a description and a gene pool in the game files.
The names Rurue, Royda, Themuma, Hadee exist in the game files without a description or a gene pool.
Two entries in the files share the name Amblyss and have identical gene pools.

Creatures

A creature in Brotula is an enemy that blocks the explorer’s way during a dive. Each species is built on a real deep-sea organism, and the species that can appear depend on the depth. A creature enters the fight with its brain cells already filled with the skills it will use.

How creatures appear

The dive is split into depth bands. At the start of each band the game picks one creature species from that band’s list.
Species names below are the internal names from the game files.
Common species have a few percent each, and rare species have 1% each. In the first band the species Kridei, Batiz, Cirrat, Plog and Pharn have 6% each, Typhlon, Bent, Aliss, Abbet and Phobel have 5% each, and the rarest species of the list have 1% each.
The deeper the dive, the shorter the list: shallow bands offer up to 44 species, the deepest band only 14.

Species by depth

Depth band (m)	Species that can appear
5100 to 5300	Abbet, Aliss, Babil, Batiz, Bent, Cellisee, Cirrat, Demos, Echin, Ekhir, Galan, Golor, Gren, Heeth, Hio, Khirond, Kridei, Lat, Lihet, Marius, Mikt, Nerrelid, Nophor, Pareed, Paster, Phanos, Pharn, Phiu, Phobel, Plog, Prokt, Sactin, Sciph, Sothet, Thanaid, Tkhar, Topel, Typhlon, Zem
5300 to 5600	the same species as above, plus Nemin, Popmp, Rago and Theus
5600 to 6650	the same species as in the previous band, plus Asce
6650 to 8470	Asce, Babil, Cellisee, Demos, Echin, Ekhir, Galan, Golor, Gren, Heeth, Hio, Khirond, Lat, Marius, Mikt, Nemin, Nerrelid, Nophor, Pareed, Paster, Phanos, Phiu, Prokt, Rago, Sactin, Sciph, Sothet, Thanaid, Theus, Tkhar, Topel, Zem
8470 to 10500	Asce, Cellisee, Demos, Ekhir, Galan, Golor, Hio, Khirond, Lat, Marius, Nemin, Nerrelid, Nophor, Pareed, Paster, Phiu, Prokt, Rago, Sactin, Sciph, Thanaid, Theus, Tkhar, Zem
10500 to 12500	Demos, Ekhir, Galan, Golor, Khirond, Marius, Nemin, Nerrelid, Paster, Sactin, Sciph, Thanaid, Tkhar, Zem

In the deepest band Khirond, Golor, Marius and Demos are among the most frequent.

Species with special behaviour

Theus mimics the player. Its cells copy the skills of the player’s last formation.
Marius puts a skill into its first cell and, according to the game scripts, leaves the other cells empty.
Pareed can draw its skills from the whole range at any depth.
All other species draw from a skill range that widens and shifts with depth.

Fish

In the band between 10500 and 11150 metres a dive can place a fish instead of a creature. According to the game scripts, a fish cannot be escaped from.

Species in the game files without regular spawns

The names Hadee, Koryph, Roid and Themum exist in the game files, but the depth bands above do not spawn them.

Glossary

Antiblock: A skill effect that keeps mental clarity while the cell is not extinguished. Icon: an open mollusc with a stone stuck between the valves. See skills.
Attack: A skill effect that lowers enemy brain cell activity (-1). Icon: a fish with a mouth. See skills.
Battle: A turn-based duel of two sets of brain cells. See battle mechanics.
Block: A skill effect that clouds the mind while the cell is not extinguished. Icon: a closed mollusc. See skills.
Brain cell: One of the nine cells in a 3×3 grid. A cell with a skill is a unit with 1 HP. See battle mechanics.
Brotula game: The name of the game, and also the name of the first social network built into human consciousness in its story. See world.
Capsule screen: The screen where the player lands after the explorer dies. Genes are set up here between dives before a new expedition starts. See README.
Caviar: The in-game resource and the explorer’s food. It gives energy, and energy is spent on training skills. See README.
Closed cell: A cell blackened by high pressure. It is invisible on the enemy’s grid and cannot be occupied on the player’s grid. See battle mechanics.
Companion: A mermaid that the player takes as a reward. A chosen companion generates genes after the next battle. See companions.
Creature: An enemy that blocks the explorer’s way during a dive. See creatures.
Dive: One expedition from the surface zone toward the sources of life and water. Skills last for one dive only. See README.
Escape: An attempt to avoid a fight by tapping your own creature. It is a chance, not a guarantee. See battle mechanics.
Explorer: The sexless deep-sea creature that the player controls. When it dies, it is replaced by a modified one. See world.
Extinguished cell: A cell that has been damaged. It stays extinguished until the end of the battle and adds 1 to the opponent’s total damage. See battle mechanics.
Formation: The arrangement of the player’s skills on the grid, set before a battle in response to the creature’s cells. See battle mechanics.
Gene: A permanent upgrade of the explorer with levels from 0 to 3. Genes carry over between dives and unlock skills. See genes.
Hint: The explanation of skill effect icons, opened by tapping the red starfish at the top right of the skills screen. See skills.
Long-lasting impulse: A skill effect (effect x3) that belongs to the poison skills. Icon: a stylized sea cucumber. See skills.
Mermaid: See Companion.
Multi-target: A skill effect marking every skill with more than one target. Icon: neural connections. See skills.
Pressure: The depth effect that closes cells 4 to 9. Genes keep specific cells open. See battle mechanics.
Reduction: A degrading state of genes: a random gene can be reduced during the next expedition. See genes.
Ringwoodite: A mineral whose crystals are the first structures that formed water on Earth. Finding them is the goal of the game. See world.
Skill: An action that the player places on a brain cell. It is learned for caviar and lasts for one dive. See skills.
Step: One turn of a single cell. A round of a battle has 18 steps, 9 for each side. See battle mechanics.
Trap: A skill effect: the cell is activated and damaged when excited (-1). Icon: a cave with a lurking creature. See skills.
Water memory: A random reward that shows a picture and a text and opens the next scene of the explorer’s backstory. See world.
Zone: A depth band of the dive with its own name, creatures and mermaids: Abyssal zone, Hydrothermal vents, Hadal zone, Trench, Trench bottom, Subduction zone. See world.