What it is

A biome is the themed visual + spawn flavor of a planet or zone — the bundle of art direction, ambient palette, terrain content, prop mix, enemy bias, and boss-arena dressing that gives a run its mood. Every player-facing planet selects one of six biomes; the biome decides what the player sees, what kinds of things they ram into, which boss they fight at T-zero, and which mastering preset is applied to the camera. Boss encounters layer a separate terrain pattern on top of the biome backdrop for the duration of the fight.

Six biomes are defined: landing site, sunrise city, the voidstar, obsidian spire, delphi, and old earth. They differ along five axes:

  1. Backdrop nebula style (palette, fog, animation, star shape).
  2. Terrain prop mix (asteroids, buildings, pillars, mixed).
  3. Camera mastering (dark or sunlit post-processing).
  4. Enemy set bias (which spawn pool the planet draws from).
  5. Boss-arena terrain pattern (open, ring, cross, hazard, corridor, gauntlet).

Stats tables

Biome catalog

BiomePlayer-facing labelTerrain contentMasteringBuildings allowedBoss-arena terrain
landing_sitescorched / grey / amber rocky plainasteroid fielddark or sunlit (per planet)yespillar ring or open
sunrise_citygolden-hour skylinebuilding gridsunlityesgauntlet
the_voidstarstarless black voidsparse mixed debrisdarknoopen
obsidian_spireobsidian pillar mazetall black columnsdarknocorridor
delphimirror-lake surface with rig platforms and sunken beamscrystal pillars and beamssunlityeshazard pads
old_earthdirty grey ground with topographic lat/long gridsquare ruined buildingsdarkyespillar cross

Planet → biome mapping

Every player-facing planet attaches a biome, an enemy set bias, a boss, and an atmospheric fog overlay. Fog alpha runs 0 (perfect void) through 0.78 (heavy haze). Enemy count multiplier and spawn grace are also per-planet so two planets sharing a biome can still feel different. Shadow multiplier scales drop-shadow Y-offset — 2.0 reads as taller buildings casting longer shadows.

PlanetBiomeEnemy biasBossFog alphaEnemy multSpawn grace (s)Shadow multMastering
LANDING SITElanding_siteorb / charger / shooter / mortarpacemaker0.151.011.0dark
SUNRISE CITYsunrise_citygunner / field / sniper / racerfirst lady0.781.012.0sunlit
THE VOIDSTARthe_voidstarorb / charger / shooter / mortarcenotaph0.002.001.0dark
SOLARISlanding_sitemortar-heavyiron throne0.201.011.0sunlit
SPEEDWAYlanding_siteshooter-heavyspire0.101.011.0dark
EDEN-5landing_sitecharger-heavygrand procession0.201.011.0sunlit
OLD EARTHold_earthsniper-heavyringmaster0.251.011.0dark
NETWORK STATIONlanding_sitefield-emitter raresforeman0.151.011.0dark
DELPHIdelphiracer-heavyapex0.151.011.0sunlit
DESOLATIONlanding_sitemortar + shooter suppression0.151.011.0dark
OBELISKlanding_siteall-rare mix0.101.011.0dark

Destructibles per biome

Each planet ships two destructible-density sliders. Both run 0–100, where 100 is the maximum density the engine supports for that category and 0 disables spawning. Crates break on ram and drop XP; debris is metal cloud that chips percentage HP and shield on contact.

PlanetCratesDebris
LANDING SITE404
SUNRISE CITY4016
THE VOIDSTAR4014
SOLARIS4011
SPEEDWAY4019
EDEN-54010
OLD EARTH4016
NETWORK STATION4015
DELPHI4012
DESOLATION4018
OBELISK4013

Terrain prop sizes

These are the on-screen sizes of biome-defining props. Asteroid sizes are reported as the diameter range after scale variance is applied; buildings and pillars ship at fixed size.

PropWhere it appearsSize (radius, px)
asteroid_smlanding_site, the_voidstar75–112
asteroid_mdlanding_site, the_voidstar85–136
asteroid_lglanding_site, the_voidstar98–156
asteroid_xllanding_site, the_voidstar100–180
rock_shardlanding_site, the_voidstar60–78
building_1x1sunrise_city, old_earth277
building_2x1sunrise_city, old_earth322
building_1x2sunrise_city, old_earth284
building_2x3sunrise_city, old_earth385
pillar_smobsidian_spire, delphi576
pillar_mdobsidian_spire, delphi768
pillar_lgobsidian_spire, delphi960

Boss-arena terrain patterns

When a boss spawns, the arena clears any biome scatter and drops in one of six static layouts. Each layout is sized to the arena and removed at encounter end. Pillar HP is 300, pillar radius is 30; hazard pads are 70-radius and apply 18 damage-per-second while the ship overlaps.

PatternLayoutUsed by
openempty arenafirst lady, cenotaph, default
pillar_ring6 destructible pillars in a circle at 65% radiushive queen archetype
pillar_cross4 destructible pillars in a + cross at 55% radiusdoomsayer archetype
hazard_pads4 damaging floor pads at 50% radiusawakened mech phase 3
corridor2 walls of 4 pillars each along the long axisreactor core
gauntlet6 low pillars staggered into two rows of 3junkrat captains

Nebula backdrop zones

The animated nebula behind every level is one of roughly 250 named archetypes. Archetypes are organized into eleven thematic zones plus seven advanced render-mode pools. The zone name on the left is the curated thematic group; the right column lists representative archetype names players see in the level intro.

ZoneToneSample archetypes
The Outer Acheronentry / thresholdSparse Silent Void, Asteroid Belt, Low Orbital, The Terminal, Watercolor Dream, Frozen Glacial, Gravity Well, Comet Trail
The Tartarus Gridindustrial / ruinAncient Ruins, Wireframe Sim, Game Boy Matrix, Cyber-Noir Rain, Steampunk Brass, Heavy Metal, Rust Foundry, Abandoned Station
The Abyssal Styxliquid / organicVerdant Cavern, Bioluminescent Deep, Eldritch Abyss, Microscopic, Blood Moon, Ink and Paper, Spore Drift, Jellyfish Bloom
The Phlegethon Wastesradiation / chaosChaos Warp, Solar Flare, Radioactive Slime, Dune Spice Storm, Darksynth, Vaporwave Highway, Lightning Storm, Magma Core
The Elysian Anomalysurreal / divineCosmic Rift, Princess Dreamland, Candy Core, Acid Psychedelia, Stained Glass, Aurora Borealis, Memory Palace, Enchanted Garden, Prism Cavern, Golden Baroque
The Aquatic Layeratmospheric hazeDusk Haze, Emerald Mist, Coral Dawn, Moonlit Haze, Amber Drift
The Fog Realmvolumetric fog overlayMorning Mist, Poison Cloud, Cinder Smoke, Dawn Haze, Phantom Fog, Nebula Veil, Ink Cloud, Pollen Storm, Volcanic Ash, Sea Spray
The Molten Coreheat-shimmer surfacesMagma Flow, Blue Flame, Sulfur Fields, Ember Rain, Solar Surface, Dragon Fire, Volcanic Night, Forge Floor
The Crystal Wastesprismatic refractionBlack Ice, Frost Cathedral, Diamond Dust, Glacier Blue, Crystal Cave, Snowblind, Arctic Night, Amber Prison, Rose Quartz
The Dark Sectorgravitational lensingEvent Horizon, Dark Matter Web, Singularity, Quantum Foam, Graviton Field, Null Space, Cosmic String, Void Bloom
The Hybrid Nexusmixed FX combinationsDrowned Temple, Plasma Storm, Thermal Vent, Frozen Lightning, Acid Ocean, Mirror Dimension, Brimstone, Ghost Reef, Neon Abyss, Celestial Furnace

Advanced render-mode pools

A second wave of archetypes routes through dedicated render modes that produce specific space phenomena rather than generic nebula fog. These run in parallel with the eleven zones above and can show up on any planet.

ModeWhat you seeMode-specific knobsPool size
Enriched classicnebula plus dense twinkle stars plus shooting-star streakssparkle intensity, shooting-star angle and variance37
Spiral / warp portalrotating galactic spiral or warp-portal funnelarms, twist, bulge25
Black holegravitational lensing with accretion ringhorizon radius, ring radius, ring width18
Planet horizonplanet-edge flyover with parallax cloud bandshorizon Y, curve amount, band speed25
Aurora ribbonsflowing additive light ribbonsribbon count, wave amplitude, vertical drift12
Warp tunnelforward-flying hyperspace tunnel with radial streakstunnel speed, intensity10
Cavernvolumetric depth-fog cavern wallsnone11

Star shapes used in the near layer

Near-layer stars are drawn as one of eight glyphs depending on archetype. The shape is a flavor knob — sharper shapes read as energetic; rounder shapes read as calm.

ShapeWhere it shows up
sqrocky, industrial, void-leaning archetypes
dotcalm, atmospheric, organic archetypes
diacrystalline, baroque, mirror archetypes
triradiation, slime, magma archetypes
hexbrass, prism, acid archetypes
star5dream, divine, enchanted archetypes
sparkflare, ember, storm, ice-shard archetypes
crosswireframe / simulation archetypes

Color and animation knobs per archetype

Each archetype tags itself with the following knobs. The values are not numbers to memorize — they are the dimensions designers tune when authoring a new biome backdrop.

KnobEffectTypical range
pa / pb / pc / pdcosine palette parameters that define the color sweep across the nebulathree-channel vectors
warpdomain-warp strength0 (flat) to 3 (chaotic)
densitynebula opacity / fill0 (sparse) to 1 (opaque)
speedpalette and animation drift rate0.02 (glacial) to 0.6 (frantic)
threshvisibility threshold — higher leaves more void around the nebula0 (full fill) to 0.7 (mostly void)
bgbackground base color tintthree-channel vector, 0–1
nfnoise frequency multiplier0.3 (smooth) to 1.5 (detailed)
ntnoise type0 = classic, 1 = ridged veins, 2 = voronoi cells
ecemission color for star glow tintsthree-channel vector, 0–255
satsaturation multiplier0.4 (washed) to 1.2 (saturated)
lumluminosity multiplier0.5 (dim) to 1.2 (bright)
fgfog overlay intensity0 (none) to 1.2 (heavy haze)
spksparkle / twinkle star intensity0 (none) to 1 (dense)
ssashooting-star base angleradians
ssvshooting-star angle variance0 (parallel) to 1 (chaotic shower)

Boss-arena surface effects

Some archetypes flag additional surface effects reserved for boss arenas. Designers turn these on when the boss fight needs an environmental hook beyond the standard backdrop.

EffectReads as
hmheat shimmer
wvwater waves
glglow / bloom
cachromatic aberration
prprismatic refraction
lngravitational lensing
smsurface scale modifier
sbsurface brightness modifier
sp / sssurface preset flags

How it works

When a player selects a planet on the hub swiper, the run loads that planet’s biome record. The biome decides the level preset (which controls terrain density and hub-and-spoke topology), the enemy set (which spawn pool the wave director draws from), the post-processing mastering preset (dark or sunlit), and whether buildings are allowed at all. The fog overlay alpha is applied per-planet over the biome, so two planets sharing the landing-site biome can still feel atmospherically different.

The nebula backdrop is selected per-level from the archetype pool, then rendered by either the classic single-program nebula renderer or one of seven advanced render modes (enriched classic, spiral, black hole, horizon, aurora, warp tunnel, cavern). When the boss spawns, the engine clears biome scatter inside the arena and drops in one of six terrain patterns for the duration of the fight. On encounter end the pattern clears and biome scatter resumes.

Per-planet meta-progression runs in parallel: completing runs and challenges on a planet awards XP toward a ten-level reward track, with rarity tiers ramping from common at levels 1–2 up to legendary at levels 9–10. Each track unlocks a planet-specific sub-event, signature ships across all rarities, two signature weapons, an alternate boss, a planet-master variant, and one permanent global buff. Harder planets require proportionally more XP (Sunrise City at 1.5× Landing Site, Voidstar at 2.0×).

Interactions

  • With ships and weapons. Each biome’s mastering preset shifts how ship and projectile colors read on screen — sunlit planets push warm tones, dark planets push cool. Signature weapons unlocked from a planet’s reward track use that planet’s enemy set as their balance reference.
  • With enemies. Enemy set bias means each biome favors specific archetypes from the 16-base roster, so the same player build solves Speedway (shooter-heavy) and Solaris (mortar-heavy) very differently.
  • With bosses. Each planet pins a specific boss at T-zero. The boss’s arena replaces biome scatter with a fixed terrain pattern selected per boss, so the biome’s normal look only frames the fight; inside the arena, the pattern dominates.
  • With destructibles. Crate density is flat across all planets at 40 of 100; debris density varies from 4 (Landing Site, almost none) to 19 (Speedway, dense metal cloud). Higher debris means more contact damage threat from drifting metal.
  • With fog. Sunrise City at 0.78 fog alpha is the haziest planet in the roster; the Voidstar at 0.0 is the only planet with no fog at all, which is why its starless void reads as “negative space”.
  • With the meta-track. Each planet’s reward track is a closed loop: rewards unlocked there gate ships, weapons, alt-bosses, and a permanent stat buff on every other planet.

What it does NOT do

  • A biome does not generate the world layout. Hub-and-spoke topology, scatter density, and asteroid placement are decided by the level preset attached to the planet, not by the biome string. The biome is only the look + feel + enemy-bias bundle.
  • A biome does not pick the boss. The boss is keyed per-planet, not per-biome, so two planets sharing the same biome can run different bosses.
  • A biome does not lock the nebula backdrop. The 250-plus archetype pool is independent of biome; any biome can show any archetype, and the eleven thematic zones are curated groupings, not biome filters.
  • A biome does not modify enemy stats. The enemy set selects which archetypes can spawn; rarity tiers and stat multipliers come from the enemy system.
  • A biome does not change boss-arena terrain. That is a separate per-boss terrain pattern that overrides whatever the biome was rendering once the encounter starts.
  • Planet 99 (Obsidian Spire) is data-only and not in the hub swiper — it exists for testing the obsidian-pillar biome and is not player-accessible.