Hidden mechanics

The math behind the tooltips. Understand this and you build top-tier without trial and error.

Per-instrument scalers

The hidden mechanic that changes everything. Each character has a unique scaler stat that multiplies its damage 1x to 9x. This is the dial to max.

Character	Formula	Max at cap
guitar	1 + min(armor x 1.2, 4)	5x (armor cap 5)
violin	1 + critChance x 2	9x (critChance cap 4)
flute	1 + speed x 2	5x (speed cap 2)
piano	1 + (maxHpBonus%) x 2	uncapped (HP scales)
drum	1 + missingHp% x 2	3x (at 0% HP)
microphone	1 + range x 2	9x (range cap 4)
tambourine	1 + luck x 2	5x (luck cap 2)
trumpet	1 + lifeSteal x 2	4x (lifeSteal stat cap 1.5)

The trick: scalers stack with damage. The scaler does not replace the damage stat. It multiplies on top. If you raise damage to cap (x4) and your scaler to cap (x5 to x9), final multiplier reaches x20 to x36 before the soft cap.

Damage formula

What happens on each shot, in order.

1. Base damage in shot-context

baseDamage = 1 x roleDamageMult x instrumentScaler
          = 1 x (0.75 to 1.4) x (1 to 9)

2. Damage multiplier in buildLoopModifiers

rawDamageMult =
  (1 + upgrades.damage x 3)         // additive, cap 4x at damage=3
  x roleDamageMult                   // 0.75 to 1.4
  x deepFocus(1.15) x suit x dress   // situational
  x berserkerMult                    // drum bloodRhythm
  x crescendoBoost                   // 1.0 to 1.4 (cap)
  x harmonicConvergence              // 1.10^3 = 1.33x (post-fix)
  x corruptionEmbrace                // 1.0 to 1.3
  x finalChorus                      // 1.25 if HP <=15%
  x extendedMelody                   // 1.15 if buff active
  x characterDamageMult              // warDrum x deathMarch x ...

damageMult = softCapDamage(rawDamageMult x surge)
SOFT_CAP = 4.0, excess x 0.6

3. Crit roll in damage.ts

critChance = max(0, upgrades.critChance)   // NO upper clamp
critMult = 1 + max(0, upgrades.critDamage) // cap 5, x6
isCrit = random() < critChance             // >=1.0 means always crit
damage = isCrit ? round(base x critMult) : base

critChance has no upper clamp. Stat cap 4 means every shot crits. Combined with critDamage cap 5 (x6 mult), violin or tambourine builds can generate astronomical damage before the soft cap. Intentional, the glass cannon identity.

Defensive stack (21 layers)

Each hit goes through this pipeline in order (player-damage-apply.ts).

Invulnerability gate: nowMs < s.fx.invulnerableUntil, full immunity
Death March (drum): 1HP invuln window, CD 30s
Jingling Shroud (tambourine): absorbs next hit
Pickup Ghost: phase through 5s
Pickup Shield: HP shield absorber
Fortissimo Barrier: consume 1 stack (cap 3)
Rhythm Shield: 2s absorb, CD 5s
Flute Tornado: full invuln during 3 to 4s tornado
Guitar Dash: 260ms invuln (rollUntil)
Tambourine Lucky Negate: chance up to 0.75. gamblersFortune heals plus invuln
Evasion roll: cap 0.95 sum (evasion plus luckyStep plus glissando plus sustainPedal plus slipstream)
Armor flat: totalArmor cap 15 (stat plus adaptive plus bonus plus battleScar plus ivoryFortress plus crowdCrush). max(1, dmg - armor)
Rosin Barrier (violin): flat reduction floor(marks/5), cap -4
Damage Reduction stat: cap 0.5 (50%) hard, multiplicative
Crowd Surf: cap 0.15 per enemy count
Sanctuary Aura (piano): 20% DR during 3s post-pulse
Rhythmic Resilience (drum): 20% DR when <50% HP
Brass Barricade (trumpet): 30% DR 1.5s post-catch
Echo Shield (trumpet): 35% DR with 3+ boomerangs in flight
Cyclone Aegis (flute): 50% DR 3s post-tornado
Resonant Barrier (microphone): 0.88^echoes, floor 0.5

Realistic stack. Multiplicative DR layers 14 to 21 are instrument-specific. A single character only stacks its own plus DR stat plus crowdSurf. Worst case: 0.5 x 0.85 x 0.5 (instrument) = 0.21, around 79% effective DR plus flat armor 15. No build reaches sustained immortality.

Stat caps reference

From src/lib/game/game/rules/stat-weights/stat-caps.ts

Stat	Cap	Notes
damage	3 (300%)	Additive in formula (1 + dmg*3)
fireRate	2	Multiplicative cooldown
range	4	Mic damage scaler
critChance	4 (400%)	No upper clamp in damage.ts, >=1.0 means guaranteed crit
critDamage	5 (x6 mult)	Multiplies baseDmg on crit
evasion	0.5 hard	Sums with relic bonuses, final cap 0.95
armor (stat)	5	Total armor (with relics) cap 15
multiHit	0.5 hard	50% chance double-shot proc
damageReduction	0.5 hard	Multiplicative
cooldownReduction	0.5 hard	Dash, abilities
lifeSteal (stat)	1.5	Operational heal cap 0.30
healingBoost	0.75	Post-heal multiplier
maxHp	no explicit cap	Piano scaler compounding
luck	2	Tambourine scaler
speed	2	Flute scaler
projectileCount	5	Bullets per shot
heal-per-frame	0.04 x maxHp	Lifesteal only (piano pulse capped at 30% per pulse)