Organs & Bosses

A full run goes nose to brain through eight organs. Each has its own look, music, local cells and tissue hazards, a key guardian holding a gene, a cancer, and a boss you must beat to break through.

8organs to infect

8organ bosses

8key guardians (mini-bosses)

3genes that open sealed doors

8organ cancers

11tissue hazard types

6boss signature skills

The Journey

Eight Organs, Nose to Brain

Every Infect Game Mode run is a descent through the host, one organ at a time. Each organ has its own map, local immune cells, hazards, key guardian, cancer, music and boss, and beating the boss opens a passage to the next organ. You can't go back once you leave.

Choose your point of entry

Eight organs, nose to brain. Pick one to see what lives there.

AREA 1

Nasal PassageMast Cell AREA 2

LungsAlveolar Macrophage AREA 3

BloodstreamPlasma Cell AREA 4

Lymph NodeFollicular Helper T Cell AREA 5

GutPaneth Cell AREA 6

LiverKupffer Cell AREA 7

Bone MarrowHematopoietic Stem Cell AREA 8

BrainMicroglia

Area 1 · Organ 1

Nasal Passage

The first organ and the place to learn. Soft pink tissue full of mucus, guarded by the Mast Cell. Cells here hit at two-thirds strength so new players can find their feet.

BossMast Cell

Key guardianMucin Colossus

CancerNasopharyngeal Carcinoma

AssassinSquamous Stalker

Objective: "Find and defeat the Mast Cell"
Boss: Mast Cell, "Guardian of the nasal passage"
Key guardian: Mucin Colossus, holding the Mucolytic Enzyme. One door is sealed by a mucus plug
Cancer: Nasopharyngeal Carcinoma (destroy the nodules shielding it, then the tumor). Its assassin is the Squamous Stalker
Hazards: 2–3 mucus puddles in every room, nerve endings that fire a Sneeze Reflex, cilia carpets
Local cells: Neutrophils and Monocytes. Deeper rooms add B Cells, Macrophages, Plasmablasts and Basophils
Look: a dark rose floor inside pink membrane walls lined with swaying cilia
Music: C Dorian at 100 BPM, a sawtooth pad and a soft triangle lead with a light swing
Size: 12–16 rooms
Threat: cells deal 0.67× damage, the gentlest organ

The real nasal passage

The air channel behind the nose, lined with mucous membrane. It warms, humidifies and filters the air you breathe.

Fun fact: Most respiratory viruses, including influenza, begin their infection here.

Area 2 · Organ 2

Lungs

Violet air-sac tissue that breathes, so a slow current sways you up and down as it inhales and exhales. The Alveolar Macrophage waits at the end.

BossAlveolar Macrophage

Key guardianSyncytium

CancerLung Adenocarcinoma

AssassinLepidic Glider

Objective: "Reach the Alveolar Macrophage"
Boss: Alveolar Macrophage, "The lungs' resident dust-eater"
Key guardian: Syncytium, holding the Fusion Peptide. One door is sealed by a tight junction
Cancer: Lung Adenocarcinoma (shoot down its metastases before they take root). Its assassin is the Lepidic Glider
Hazards: nerve endings that fire a stronger Cough Reflex, cilia carpets, air sacs on the walls, breathing currents
Local cells: Neutrophils, B Cells, Macrophages, Monocytes and Plasmablasts. Deeper rooms add antiviral capsules, vaccine vials and Eosinophils
Look: a plum floor scattered with gently pulsing alveoli
Music: D minor at 92 BPM, a triangle pad and a sine lead with no swing
Size: 14–18 rooms
Threat: enemy damage ×1.0, enemy health ×1.1, rewards ×1.5 (compared with the Nasal Passage)

The real lungs

The organs of breathing, where oxygen enters the blood and carbon dioxide leaves it.

Fun fact: Spread flat, the surface of the lungs' air sacs would cover roughly half a tennis court.

Area 3 · Organ 3

Bloodstream

A rushing crimson vessel. The blood flow shoves you along with every heartbeat while red blood cells stream past. Ride the current to the Plasma Cell.

BossPlasma Cell

Key guardianFibrin Weaver

CancerLeukemia

AssassinCirculating Blast

Objective: "Ride the current to the Plasma Cell"
Boss: Plasma Cell, "The immune system's antibody factory"
Key guardian: Fibrin Weaver, holding the Plasminogen Activator. One door is sealed by a fibrin clot
Cancer: Leukemia (cancer cells keep dividing, so find and kill the glowing stem cell). Its assassin is the Circulating Blast
Hazards: a pulsing blood flow and solid red blood cells. There are no nerve endings here because blood has no sensory endings
Local cells: Platelets in clumps, Neutrophils, Natural Killer Cells, Complement, Macrophages, Monocytes, Plasmablasts and Basophils. Deeper rooms add Dendritic Cells, antiviral capsules, vaccine vials and Memory B Cells
Look: a deep red floor with streams of red blood cells and streaks of flow
Music: B-flat harmonic minor at 116 BPM with a square-wave lead
Size: 17–21 rooms
Threat: enemy damage ×1.2, enemy health ×1.85, rewards ×2.2

The real bloodstream

The network of vessels carrying about 5 litres of blood around the body every minute, filled with red cells, platelets and immune cells.

Fun fact: Laid end to end, your blood vessels would stretch around 100,000 km, more than twice around the Earth.

Area 4 · Organ 4

Lymph Node

The immune system's checkpoint: blue follicles crowded with lymphocytes and organised by helper T cells. From here on, each organ is much harder than the last.

BossFollicular Helper T Cell

Key guardianReticular Warden

CancerLymphoma

AssassinOwl-Eye Mimic

Objective: "Break the Follicular Helper T Cell's command"
Boss: Follicular Helper T Cell, "Commander of the germinal centre"
Key guardian: Reticular Warden (Awakened), holding the Plasminogen Activator
Cancer: Lymphoma (clones hide among harmless lymphocytes, and the germinal centre is only vulnerable while it swells). Its assassin is the Owl-Eye Mimic
Hazards: reticular fibres strung across the rooms
Local cells: Free Antibodies, B Cells, Helper T Cells, Plasmablasts, NK Cells, Monocytes, Thymocytes, Lymphoid Progenitors and Basophils. Deeper rooms add Follicular Dendritic Cells, Dendritic Cells, vaccine vials and Memory B Cells
Look: a navy floor with pale follicle rings and lymphocytes drifting past
Music: C-sharp Dorian at 108 BPM, swung
Size: 18–22 rooms
Threat: enemy damage ×2, enemy health ×4, rewards ×2.8

The real lymph node

A bean-sized checkpoint where immune cells gather. Lymph drains through it, and B and T cells meet the antigens dendritic cells bring in.

Fun fact: You have around 600 lymph nodes; swollen glands during a cold are nodes busy fighting.

Area 5 · Organ 5

Gut

A golden intestinal lining with finger-like villi swaying along the walls. Goblet cells lob mucus here, and the Paneth Cell guards the crypts.

BossPaneth Cell

Key guardianCajal Pacemaker

CancerColon Carcinoma

AssassinSignet-Ring Burrower

Objective: "Get past the Paneth Cell's defensins"
Boss: Paneth Cell, "Keeper of the intestinal crypts"
Key guardian: Cajal Pacemaker (Awakened), holding the Mucolytic Enzyme
Cancer: Colon Carcinoma (it hides in its crypts, so watch where it surfaces and dodge the polyps' pools). Its assassin is the Signet-Ring Burrower
Hazards: peristaltic waves that sweep the room
Local cells: Neutrophils, Goblet Cells, IgA Plasma Cells, Free Antibodies, Macrophages and Eosinophils. Deeper rooms add Helper T Cells, antiviral capsules and Complement
Look: a dark amber floor, swaying villi and drifting golden specks
Music: A Phrygian at 98 BPM, the darkest and most swung theme
Size: 19–23 rooms
Threat: enemy damage ×3.2, enemy health ×6.5, rewards ×3.4

The real gut

The intestines: a lining of finger-like villi covered in mucus, home to trillions of bacteria and about 70% of the body's immune cells.

Fun fact: Spread flat, the small intestine's surface would cover about half a badminton court.

Area 6 · Organ 6

Liver

The body's filter. Rust-red hexagonal lobules, each with a dark central vein, patrolled by near-invisible NKT cells and stellate cells that leave scar tissue behind.

BossKupffer Cell

Key guardianPolyploid Hepatocyte

CancerHepatocellular Carcinoma

AssassinHepatoid Regenerator

Objective: "Survive the Kupffer Cell's filter"
Boss: Kupffer Cell, "The liver's resident filter"
Key guardian: Polyploid Hepatocyte (Awakened), holding the Fusion Peptide
Cancer: Hepatocellular Carcinoma (it regenerates from its lobes, so kill every lobe before they regrow, then strike). Its assassin is the Hepatoid Regenerator
Hazards: bile ducts that spray jets across the room
Local cells: Neutrophils, Stellate Cells, NKT Cells, Macrophages, Monocytes and Complement. Deeper rooms add IgA Plasma Cells, antiviral capsules and vaccine vials
Look: a dark rust floor tiled with hexagonal lobules and central veins
Music: B minor at 104 BPM, a triangle pad under a sawtooth lead
Size: 20–24 rooms
Threat: enemy damage ×7.5, enemy health ×19, rewards ×4

The real liver

The body's chemical factory and filter. Blood from the gut flows through its hexagonal lobules, where resident macrophages catch anything foreign.

Fun fact: The liver can regrow from as little as a quarter of its original size.

Area 7 · Organ 7

Bone Marrow

The blood-cell factory inside the bone: pale trabecular struts and fat cells, where megakaryocytes shed platelets and myeloblasts burst into neutrophils.

BossHematopoietic Stem Cell

Key guardianGiant Osteoclast

CancerMultiple Myeloma

AssassinLytic Stalker

Objective: "Take over the Hematopoietic Stem Cell"
Boss: Hematopoietic Stem Cell, "Mother of every blood cell"
Key guardian: Giant Osteoclast (Ancient), holding the Mucolytic Enzyme
Cancer: Multiple Myeloma (dodge its antibody spirals when they lock on, and keep off the bone lesions). Its assassin is the Lytic Stalker
Hazards: stem cell niches you can burst for health
Local cells: Myeloblasts, Megakaryocytes, Platelets, Neutrophils, Monocytes, Plasmablasts, Eosinophils and Lymphoid Progenitors. Deeper rooms add NKT Cells, Helper T Cells and vaccine vials
Look: a bone-brown floor crossed by cream bone struts and pale fat cells
Music: E-flat harmonic minor at 120 BPM, the fastest theme
Size: 21–25 rooms
Threat: enemy damage ×9.5, enemy health ×28, rewards ×4.7

The real bone marrow

Soft tissue inside bones where every blood cell is made: hundreds of billions a day, from a small pool of stem cells.

Fun fact: Your marrow makes about 2 million new red blood cells every second.

Area 8 · Organ 8 · Final

Brain

The last organ, behind the blood-brain barrier: a dark violet web of neurons with sparks running along it. Every cell here takes 38% less damage from you.

BossMicroglia

Key guardianBetz Cell

CancerGlioblastoma

AssassinGlial Infiltrator

Objective: "Cross the barrier and defeat the Microglia"
Boss: Microglia, "The brain's last line of defence". Beating it wins the run
Key guardian: Betz Cell (Ancient), holding the Fusion Peptide
Cancer: Glioblastoma (tendrils creep toward you and the core hops between nodes, so cut the nodes down). Its assassin is the Glial Infiltrator
Hazards: synapses that arc between neuron pairs, and the blood-brain barrier, announced as you arrive
Local cells: Astrocytes, Resident Memory T Cells, NK Cells, Monocytes, Free Antibodies, Thymocytes and Memory B Cells. Deeper rooms add NKT Cells, Follicular Dendritic Cells, antiviral capsules and vaccine vials
Look: a deep indigo floor with a web of neurons and sparks running along it
Music: C Lydian at 88 BPM, the slowest and brightest theme
Size: 22–26 rooms
Threat: enemy damage ×12.5, enemy health ×34, rewards ×5.5

The real brain

Protected by the blood-brain barrier, the brain has its own immune system run mostly by microglia and astrocytes.

Fun fact: The brain has around 86 billion neurons and roughly as many glial cells supporting them.

Boss Fights

The Eight Organ Bosses

At the end of every organ, a giant immune cell guards the way on. Bosses pick their attacks at random, never repeat the same one twice in a row, aim where you're heading, and get more dangerous as their health drops.

How Boss Fights Work

All bosses

Every boss uses the same three-stage structure: an enraged half, two shield phases with reinforcements, and a final frenzy.

The boss starts on the far side of the room from where you came in, and the room stays sealed until it falls
Attacks come on an uneven rhythm, never the same one twice in a row, aimed where you're going
Below 50% health it enrages: about 30% faster attacks and bigger volleys
At 2/3 and 1/3 health it raises a shield worth 18% of its max health and calls in reinforcements. Break the shield first

5 more

After the second shield it enters FINAL PHASE: attacks come 30% faster and every attack also throws a slow ring of 12 shots
Big attacks are telegraphed with flashing circles, lanes and on-screen calls like SNEEZE!, ENGULF! and SHOCKWAVE!
Every boss drops a named set piece of gear (the organ's best tier 40% of the time, one tier lower 45%, two tiers lower 15%) plus 3–5 Chaperone Proteins, 1–2 Ribozyme Cores (in Endless Game Mode; anywhere else they condense into 2 or 4 more Chaperone Proteins), and a chance of RNA and a Dormant Virion
Retrovirus deals 50% extra damage to bosses
Beating a boss opens a passage to the next organ and leaves a DNA upgrade orb. The last boss ends the run in victory

Mast Cell

Boss · Nasal Passage

A spinning orange cell packed with histamine. It circle-strafes the middle of the room and floods it with bursts. The counter is to stay close, because it never sneezes up close.

Histamine Burst: a ring of 14 shots, or 20 followed by a second offset ring when enraged
Sneeze: it swells and releases a room-wide shockwave ring you have to dash through. It never sneezes when you're close, and the farther you hang back the more often it does (up to about every other attack)
Histamine Charge: a marked lane and a 0.75 s wind-up (0.55 s enraged), then it rushes across the room. Dodge it and it is EXPOSED for 1.6 s, taking double damage
Aimed fan of 5 shots. Once enraged, this becomes a call for 3 Neutrophils

2 more

Each shield phase calls in 4 Neutrophils
Trophy gear: Histamine Crown, Mantle, Lattice, Talons or Lance (Hemagglutinin Array set)

Alveolar Macrophage

Boss · Lungs

A huge, slow, breathing phagocyte. It never stops lashing pseudopods at you and alternates between engulfing you and releasing surfactant bubbles.

Pseudopod Lash: on its own clock every 1–3 s, a telegraphed tendril straight at you. When enraged it lashes three at a time in a spread
Phagocytosis (Engulf): "INHALING…" with a ring sweeping inward for 0.7 s, then it drags you in for 2.2 s. Dashing breaks free, and its open core takes double damage
Surfactant Bubbles: 4 bubbles (6 enraged) drift after you and pop into rings of 8 shots. Once enraged it also calls 3 Neutrophils
It moves 50% faster once enraged

3 more

Each shield phase calls in 5 Neutrophils
Its chamber hits 20% harder than the rest of the Lungs
Trophy gear: Surfactant pieces (Lipid Bilayer set)

Plasma Cell

Boss · Bloodstream

The antibody factory. It drifts and strafes behind a turning Immunoglobulin wall, so you have to circle around it while dodging antibody fans and platelet swarms.

Immunoglobulin Wall (IG WALL): every 4–7 s it raises a glowing arc on one side that slowly turns to follow you for 4.5 s. Hits from the front deal only 15% damage
Antibody Snipe (signature): a fast shot that forks into a Y just before it reaches you. It fires two when enraged
Antibody Fan: 12 slowing antibodies (17 enraged)
Opsonize: a flashing lock-on line, then a fast 8-shot volley. Each hit marks you to take 35% more damage for 5 s

4 more

Rapid Stream: 9 shots (12 enraged) at where you're going
Platelet Swarm: 7 Platelets (10 enraged), plus a 16-shot spiral ring once enraged
Each shield phase calls in 2 Natural Killer Cells
Trophy gear: Plasma pieces (Replicase Complex set)

Follicular Helper T Cell

Boss · Lymph Node

Commander of the germinal centre: a bristling blue lymphocyte that whips the whole room into a cytokine storm and keeps calling in B cells and helper T cells.

Germinal Center (signature): marks a circle where you're heading, then 9 antibodies (12 enraged) converge on it from all sides
Cytokine Storm: every other cell in the room gets faster and hits harder for 6 s, and non-boss cells gain a shield worth 20% of their health
Radial burst of 16 shots (22 enraged)
Summon: 4 B Cells, Plasmablasts or Helper T Cells (5 enraged)

5 more

Aimed fan of 7 (9 enraged)
Shockwave: an expanding ring to dash through
Rapid stream of 8 (11 enraged)
Each shield phase calls in 3 Helper T Cells
Trophy gear: Germinal pieces (Glycan Shield set)

Paneth Cell

Boss · Gut

Keeper of the intestinal crypts, full of gold defensin granules. Expect spiralling defensin streams, mucus barrages and granules lobbed right onto you.

Defensin Granule (signature): lobbed onto where you're going. It hurts if you're under it when it lands, then bursts into a ring of 10 defensins. It throws two when enraged
Spiral: 4 turning arms of shots (6 waves, 8 enraged)
Mucus Barrage: 5 warning circles (7 enraged) that land as hurtful, slowing puddles
Radial burst of 20 (26 enraged)

5 more

Bubbles: 4 (6 enraged) that drift after you and pop into rings of 8 shots
Aimed fan of 9 (11 enraged)
Rapid stream of 9 (12 enraged)
Each shield phase calls in 3 Goblet Cells
Trophy gear: Mucosal pieces (Capsomere Lattice set)

Kupffer Cell

Boss · Liver

The liver's resident filter, a lumpy macrophage that nets you in crossing lashes, engulfs you and charges. It attacks on a quicker rhythm than the other bosses.

Sinusoid Net (signature): 2 lashes (3 enraged) that cross exactly where you stand
Pseudopod Lashes: a telegraphed spread of 3, or 4 in every direction when enraged
Engulf: pulls you in for 2.2 s while its exposed core takes double damage
Scar Pools: 6 (8 enraged) lobs land on warning circles around you and leave slowing patches

5 more

Charge: it swells and flashes for 0.55 s, then lunges. A dodged lunge leaves it EXPOSED for 1.2 s, taking double damage
Radial burst of 18 (24 enraged)
Rapid stream of 9 (12 enraged)
Each shield phase calls in 4 Stellate Cells
Trophy gear: Kupffer pieces (Polymerase Engine set)

Hematopoietic Stem Cell

Boss · Bone Marrow

The mother of every blood cell. It keeps making new ones (neutrophils, myeloblasts, platelets, even megakaryocytes and NK cells) between bursts, spirals and bone spikes.

Spicule Eruption (signature): bone spikes burst out of the floor one after another in a marked line from it through you, 4 spikes (6 enraged)
Summon: 5 Neutrophils, Monocytes or Myeloblasts (6 enraged)
Summon: a swarm of 8 Platelets (9 enraged)
Summon: 2 Megakaryocytes or NK Cells (3 enraged)

7 more

Radial burst of 22 (28 enraged)
Spiral: 5 turning arms of shots
Shockwave ring to dash through
Rapid stream of 10 (13 enraged)
When 12 summoned cells are already alive, it fires a burst instead of summoning more
Each shield phase calls in 4 Myeloblasts
Trophy gear: Marrow pieces (Integrase Core set)

Microglia

Final Boss · Brain

The brain's last line of defence: a branching violet cell that lashes in every direction, summons glia and strikes down marked lines with lightning. Every hit you land is weakened by the blood-brain barrier.

Synaptic Prune (signature): a line flashes from it to where you're going, then lightning strikes down it 0.6 s later. It uses two angled lines when enraged
Lashes in every direction: 4 tendrils (5 enraged) spread around it
Spiral: 6 turning arms of shots
Summon: 3 Astrocytes or Resident Memory T Cells (4 enraged)

7 more

Engulf: drags you in while its exposed core takes double damage
Radial burst of 24 (30 enraged)
Charge: a lunge that leaves it exposed if you dodge
Rapid stream of 11 (14 enraged)
Each shield phase calls in 3 Astrocytes
Beating it ends the run: TOTAL INFECTION
Trophy gear: Microglial pieces (Neurotropic Crown set)

Keys & Locks

Key Guardians, Genes and Sealed Doors

Every organ seals one door with living tissue. The gene that opens it waits in a gene chamber guarded by a key guardian mini-boss, and every organ has a different guardian. Beat it, splice the gene into yourself, and the gene's bonus stays with you for the rest of the run.

A Giant Osteoclast (Ancient) guarding the Bone Marrow

Sealed Doors

Every organ

Each organ seals one doorway with a mucus plug, a tight junction or a fibrin clot. It won't open until you carry that organ's gene.

Details

About two times in three the sealed door is on the way to the boss. Otherwise it locks the organ's Upgrade Chamber
Walk into it without the gene and you're turned back: "SEALED BY A MUCUS PLUG / TIGHT JUNCTION / FIBRIN CLOT: find the Mucolytic Enzyme / Fusion Peptide / Plasminogen Activator somewhere on this organ"
Carry the right gene and the door dissolves for good: "DISSOLVED", "FUSED THROUGH" or "CLOT LYSED"
Mucus plugs: Nasal Passage, Gut, Bone Marrow. Tight junctions: Lungs, Liver, Brain. Fibrin clots: Bloodstream, Lymph Node

Gene Chambers

Every organ

A fight room holding a strand of foreign DNA you can splice into yourself, guarded by the organ's key guardian.

Details

Always placed so you can reach it without passing the sealed door, often in a dead end
Entering it announces its KEY GUARDIAN. When the gene appears: "GENE CHAMBER: a strand of foreign DNA you can splice into yourself"
When the guardian falls, the gene appears in the middle of the room as a glowing helix. Walk into it to take it
Each gene opens its door type and gives a passive bonus for the rest of the run

Mucolytic Enzyme

Gene · Organs 1, 5, 7

Dissolves mucus plugs. Mucus no longer slows you.

Details

Opens the sealed doors of the Nasal Passage, Gut and Bone Marrow
Without it, mucus puddles cut your speed to 40%
Guarded by the Mucin Colossus (Nasal Passage), the Cajal Pacemaker (Gut) and the Giant Osteoclast (Bone Marrow)

Fusion Peptide

Gene · Organs 2, 6, 8

Slips through tight junctions. Your dash damages cells you pass through.

Details

Opens the sealed doors of the Lungs, Liver and Brain
Every dash (or blink) deals 25 damage to each cell it passes through
Guarded by the Syncytium (Lungs), the Polyploid Hepatocyte (Liver) and the Betz Cell (Brain)

Plasminogen Activator

Gene · Organs 3, 4

Dissolves fibrin clots. Platelet clots no longer slow you.

Details

Opens the sealed doors of the Bloodstream and Lymph Node
Without it, clot patches (left by dying platelets, stellate scar tissue and fibrin attacks) cut your speed to 20% for the 7 s they last
Guarded by the Fibrin Weaver (Bloodstream) and the Reticular Warden (Lymph Node)

Key Guardian Rules

Mini-boss

Guardians are mini-bosses labelled KEY GUARDIAN. Each gene's guardian gets meaner every time you meet it deeper in the body.

Details

Stages: the second organ with the same gene meets an AWAKENED guardian and the third meets an ANCIENT one. Each stage adds +25% health, +15% damage, 15% faster attacks and more projectiles or adds
The first guardian (Nasal Passage) is a lighter test: 40% health and 55% damage
Every guardian throws a hook every 4.5–6.5 s after a 0.45 s warning line. 80% of throws are aimed where you're going. If it catches you, you take 8 damage and get reeled in for up to 2.5 s with no dashing out ("HOOKED!")
Each one also fires its own aimed shot every 0.9–1.8 s
Below half health its attacks come 25% faster
Too big to be flung into pits or shoved by hazards
Defeat drops nucleotides, Polymerase Shards (6, +3 per stage), Chaperone Proteins (1, +1 per stage), a 35% chance of gear and a 25% chance of RNA, then the gene

Mucin Colossus

Guardian · Nasal Passage

A living mucus plug that guards the Mucolytic Enzyme. Stay out of its puddles and fight its pull.

Details

Glob Lob: 3 warning circles (the first one right on you) that land as slowing mucus puddles
Sticky Spray: a fan of 7 slowing globs
Engulf: a pulsing ring around it hauls you in for 1.4 s and digests you every half second while you're inside. Dash out
Aimed shot: 3 slowing globs
The first key guardian most players meet, tuned as a lighter test

Syncytium

Guardian · Lungs

Fused cells with several nuclei in one membrane, guarding the Fusion Peptide. Sidestep its lunges and watch for split-off fragments.

Details

Lunge: marks a line for 0.45 s, then charges down it and lands in a ring of 10 membrane shards
Fused Volley: a quick stream of 5 shards at where you're heading
Membrane Pulse: a double ring of shots, offset and at two speeds
Cells Split Off: at 2/3 and 1/3 health it sheds 2 fused fragments that hunt you
Aimed shot: a stream of 4
Faster on its feet than the other two original guardians

Fibrin Weaver

Guardian · Bloodstream

A living clot guarding the Plasminogen Activator. Keep clear of where its fibrin lands.

Details

Keeps its distance and circles you while it weaves
Clot Ring: 5 warning circles land in a ring around you, each leaving a sticky fibrin clot
Fibrin Thread: a long line of 8 slowing shots that stretches out toward you
Calls in 2 Platelets ("PLATELETS!")
Aimed shot: twin fast, slowing shots

Reticular Warden

Guardian · Lymph Node

A star-shaped scaffold cell (Awakened) guarding the Plasminogen Activator. It strings a cage of conduit threads around you that closes to nothing.

Details

Darts in quick hops to a new spot around you, then rests a moment
Conduit Web: 6 anchors land in a ring around you, the threads flicker for 0.9 s, then go live and pull the ring shut over 2.2 s. One side is always left open, or dash across a thread
Sweep: it anchors itself and swings a long thread through a wide arc around itself after its reach flashes
Conduit Volley: two waves of 6 shots down its arms
Aimed shot: twin shots

Cajal Pacemaker

Guardian · Gut

The gut's electrical pacemaker (Awakened), guarding the Mucolytic Enzyme. It sets the whole room contracting.

Details

Peristalsis: 2 bands of contraction roll from wall to wall across the whole room, each with a gap to slip through. The gap glows green at the wall first, and getting caught hurts and shoves you
Segmentation: the floor splits into 6 strips and alternate strips flash and clench in turn, so you hop from strip to strip
Mucin Spray: a fan of 7 slowing globs
Aimed shot: one big slowing glob
Keeps a middle distance, circling, and pulses with a steady electrical beat

Polyploid Hepatocyte

Guardian · Liver

A two-nucleus liver cell (Awakened) guarding the Fusion Peptide. Its rings turn toxic one after another.

Details

Circles you at its own distance, switching direction when it bumps into something, and backs off if you corner it
Zonation: three rings around itself. Two turn toxic after a 1 s warning while one stays safe, then they flip
Bile Canaliculi: a star of 3 crossing lines (6 rays) bursts through where you're going after a 0.9 s warning
Bile Lobs: 4 lobs that leave bile pools for 3 s
Aimed shot: two side-by-side shots, one per nucleus

Giant Osteoclast

Guardian · Bone Marrow

A huge bone-dissolving cell (Ancient) guarding the Mucolytic Enzyme. It burrows after you and erupts where it surfaces.

Details

Burrowing: it sinks out of reach for 2.2 s while a crack tracks you, then erupts after a 0.7 s warning circle in a ring of 14 bone shards, leaving a resorption pit that hurts to stand in for 5 s. As an Ancient guardian it burrows and erupts twice in a row
Acid Etch: 5 lobs that dissolve damaging pits into the floor
Trabecular Collapse: bone gives way in a rolling line of 9 marked circles toward you and past
Aimed shot: a 3-shot spread
It can't be hit while burrowed

Betz Cell

Guardian · Brain

A giant motor neuron (Ancient) guarding the Fusion Peptide. Watch the lines: it leaps along them in a chain, then goes refractory.

Details

Saltatory Leap: a chain of 3 leaps, each along a line that flashes for 0.55 s and then discharges
Refractory: after the chain it greys out for 1.6 s, can't act and takes double damage ("REFRACTORY · HIT IT NOW")
Dendritic Discharge: a fan of 7 lightning lines toward you after a 0.8 s warning, then a second fan into the gaps
Synaptic Release: vesicles burst on warning circles under you and at 6 spots around you
Aimed shot: a stream of 3
Flits around you at range

Living Tissue

Hazards and Terrain

The host's own tissue fights back, but it doesn't take sides. Every organ has its own hazards, and they hurt immune cells as much as you or more, so the trick is to lure the immune system into them. Organ hazards unlock for your whole save when any virus reaches level 8, and the organ where they first appear has them in every fight room.

Nerve Endings

Nasal Passage · Lungs

Glowing nerve fibres in the walls. Linger on one and it fires a reflex that flings you and every cell nearby away from the wall.

Details

Found in about 45% of Nasal Passage fight rooms, 40% of Lungs fight rooms, and every boss room in those two organs
Stand on one for about half a second and it fires: a Sneeze Reflex in the nose, or a bigger Cough Reflex in the lungs
The blast hurts every cell caught in it (24 in the nose, 30 in the lungs) and you a little (8 / 10)
Set it off yourself and Detection rises. Shoot near it and it fires at once, and the host blames the cells
Cells flung into an abyss die. It recharges after 7 s

Cilia Carpets

Nasal Passage · Lungs

A carpet of beating hairs that carries anything on it the way the arrows point: you, cells, everything.

Details

In about 35% of fight rooms, 1–2 carpets per room
Dash to cross against the flow
Cells swept into a pit die ("SWEPT AWAY!")

Air Sacs

Lungs

Alveoli on the walls swell up, then exhale a gust that blows you and cells away and clears enemy shots.

Details

In about half of Lungs fight rooms, 1–2 per room
They swell for about a second as a warning
The gust reaches about 300 units in a cone, hits cells for 16 and wipes out enemy shots
Exhales again every 5.5 s

Red Blood Cells

Bloodstream

Solid discs drifting with the pulsing blood flow. They shove you around and soak up shots from both sides.

Details

In about 60% of Bloodstream fight rooms, 4–6 at a time
They push you and ordinary cells out of the way
They block enemy shots as well as yours. Three of your shots burst one
A fresh one drifts in from upstream 5 s later

Reticular Fibres

Lymph Node

Fibres strung across the node. Touching one slows you to under a third of your speed, and cells get snagged too.

Details

In about half of Lymph Node fight rooms, 2–3 strands
They slow you to 30% speed while you touch them
Any two shots (yours or the immune system's) snap a strand ("SNAP")

Peristalsis

Gut

Every few seconds the gut wall clenches and a wave sweeps across the room, carrying everything with it.

Details

In about 45% of Gut fight rooms
A flashing band and a "PERISTALSIS" call give about a second of warning
The wave crosses the room in 1.8 s and repeats about every 7 s
Dash through it. Cells it pushes into pits die

Bile Ducts

Liver

Ducts in the walls spray a corrosive jet of bile straight across the room after a flashing warning line.

Details

In about half of Liver fight rooms, 1–2 ducts
The warning line flashes for about 0.9 s, then the jet lasts 0.6 s
The jet deals 12 damage to you but 45 to every cell it crosses
Fires again every 5 s

Stem Cell Niches

Bone Marrow

A pod of young blood cells. Burst it to heal, but fresh neutrophils pour out.

Details

In about half of Bone Marrow fight rooms, 1–2 pods
Touch or shoot one to burst it and heal 12% of your max health
Two new Neutrophils come out already hunting you

Synapses

Brain

Pairs of neurons that fire an electric arc between them every few seconds after a flickering warning.

Details

In about half of Brain fight rooms, 1–2 neuron pairs
The line flickers for 0.8 s, then the arc crackles for about half a second
The arc deals 10 damage to you but 40 to every cell it crosses
It fires every 4 s. Shoot a neuron to fire it early

Abyss Pits

Any organ

Bottomless gaps in the tissue. Falling in is a heavy blow, not instant death.

Details

About a third of fight rooms open into pits
Falling in costs 35% of your max health, and you climb back out at the edge. It only kills you if that takes you to 0
You can't fall while dashing, so dash over them
Cells shoved in by cilia, peristalsis or a nerve blast fall and die

Drop Shafts

Rare

A rare glowing shaft in one of an organ's deeper fight rooms. Walk in and the current sweeps you into a freshly shuffled layout of the organ.

Details

About a 15% chance per organ layout
Landing announces "SWEPT AWAY: the current carries you somewhere new"
You land with a moment of invulnerability, and hunting Killer T cells lose your trail

Mucus Puddles

Nasal Passage

Green puddles of mucus that slow you down unless you carry the Mucolytic Enzyme.

Details

2–3 puddles in every Nasal Passage room, more in bigger rooms
They cut your speed to 40% while you're in them
The Mucin Colossus leaves more puddles behind

Clots & Scar Tissue

Bloodstream & deeper

Sticky patches of clot left by dying platelets, fibrin attacks, goblet mucus and stellate scarring. They bog you right down.

Details

Each patch slows you to 20% speed and lasts 7 s
Platelets leave one where they die, and Stellate Cells leave scar tissue as they move
The Plasminogen Activator gene makes you immune to the slow
A dying Basophil's heparin dissolves nearby platelet clots

Blood Flow

Bloodstream

The current pushes you in pulses that are strongest on each heartbeat, about 69 beats a minute.

Details

Each room's flow runs in one of four directions
It doesn't push you while you dash
Red blood cells drift with the same pulse

Breathing Currents

Lungs

The lungs keep breathing, swaying you gently up and down in a slow rhythm all through the organ.

Details

Applies in every Lungs room
Air sacs on the walls add sudden gusts on top

Blood-Brain Barrier

Brain

The brain's shield. Every hostile cell in the Brain takes 38% less damage from you.

Details

Announced as you arrive: "BLOOD-BRAIN BARRIER: every cell here takes 38% less damage"
It applies to everything you hit there, including the Microglia

The End

When the Brain Falls

Defeat the Microglia in Infect Game Mode and the host is yours.

Total Infection

Victory

Beating the final boss plays the Total Infection ending: all eight organs light up in turn along a spreading green line, from the nose to the brain.

The screen shows your generation number and virus, then the eight organ medallions light up one by one
"TOTAL INFECTION: You have fully infected the host" appears as the whole screen pulses green
"From the first cell in the nose to the last neuron in the brain, every organ now runs on your code."
"The immune system has nothing left to send. The host is yours."
Final stats: 8/8 organs taken, rooms cleared and cells destroyed. Continue leads to the run summary

Next up

The Immune System

Real immune cells with real jobs, and a host that escalates when it notices you.

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