Further Tweaks to Colorado Defense

src/games/coloradodefense/ColoradoDefenseLogic.js

@@ -64,6 +64,11 @@ export const TUNE = {
   MIRV_RESPLIT_WAVE: 8,
   SPLIT_ZONE_1: [0.20, 0.333],
   SPLIT_ZONE_2: [0.45, 0.55],
+  // A MIRV's own children fly slower than a regular missile right when
+  // MIRVs are introduced, then quickly catch up to full speed.
+  MIRV_CHILD_SPEED_MULT_BASE: 0.65,
+  MIRV_CHILD_SPEED_MULT_GROWTH: 0.5,
+  MIRV_CHILD_SPEED_MULT_MAX: 1.0,
   BASE_AMMO: 10,
   BLAST_R_BASE: 90, BLAST_GROW_MS: 350, BLAST_HOLD_MS: 120, BLAST_FADE_MS: 200,
   INTERCEPTOR_SPEED: 900,
@@ -118,6 +123,15 @@ export function mirvChance(wave) {
   return Math.min(TUNE.MIRV_CHANCE_MAX, TUNE.MIRV_CHANCE_BASE + TUNE.MIRV_CHANCE_GROWTH * (wave - TUNE.MIRV_WAVE));
 }
 
+// How fast a MIRV's split-off children fly, relative to a normal missile
+// that wave — starts slow right when MIRVs are introduced, ramps to full speed.
+export function mirvChildSpeedMult(wave) {
+  return Math.min(
+    TUNE.MIRV_CHILD_SPEED_MULT_MAX,
+    TUNE.MIRV_CHILD_SPEED_MULT_BASE + TUNE.MIRV_CHILD_SPEED_MULT_GROWTH * (wave - TUNE.MIRV_WAVE),
+  );
+}
+
 // Automatic, level-driven palette progression (distinct from user-facing
 // pickers like 2048's) — advances every PALETTE_WAVES waves, clamped at the end.
 export const PALETTES = [
@@ -127,7 +141,7 @@ export const PALETTES = [
   { bgTop: 0x1a140a, bgBottom: 0x301c0a, trail: 0xffb366, explosion: 0xff5555, accent: 0xff8a3c, ground: 0x2a1c0f, chain: 0xffee88 },
   { bgTop: 0x120a1a, bgBottom: 0x260a30, trail: 0xc78dff, explosion: 0xff66c4, accent: 0xb84bff, ground: 0x1e0f2a, chain: 0x66ffcc },
 ];
-export const PALETTE_WAVES = 4;
+export const PALETTE_WAVES = 2;
 export function paletteIndexForWave(wave) {
   return Math.min(PALETTES.length - 1, Math.floor((wave - 1) / PALETTE_WAVES));
 }
@@ -216,13 +230,13 @@ export class Sim {
   // only a freshly-spawned, top-edge missile can randomly become one; a
   // MIRV's own children (fromOverride, no force) are always simple 'single's
   // so the split tree stays bounded.
-  spawnEnemyMissile(fromOverride, forceMirv = false) {
+  spawnEnemyMissile(fromOverride, forceMirv = false, speedMult = 1) {
     const target = this.pickTargetSlot();
     if (!target) return null;
     const fromX = fromOverride ? fromOverride.x : 80 + this.rng() * (WIDTH - 160);
     const fromY = fromOverride ? fromOverride.y : 0;
     const dist = Math.hypot(target.x - fromX, target.y - fromY);
-    const speed = fallSpeed(this.wave);
+    const speed = fallSpeed(this.wave) * speedMult;
     const dur = Math.max(200, (dist / speed) * 1000);
     const isMirv = forceMirv || (!fromOverride && this.rng() < mirvChance(this.wave));
     const kind = isMirv ? 'mirv' : 'single';
@@ -241,9 +255,10 @@ export class Sim {
     const options = TUNE.MIRV_CHILDREN;
     const n = options[Math.floor(this.rng() * options.length)];
     const cur = lerpPos(parent);
+    const speedMult = mirvChildSpeedMult(this.wave);
     const children = [];
     for (let i = 0; i < n; i += 1) {
-      const m = this.spawnEnemyMissile(cur);
+      const m = this.spawnEnemyMissile(cur, false, speedMult);
       if (m) children.push(m);
     }
     return children;

tools/verifyColoradoDefense.js

@@ -7,6 +7,7 @@
 // 3. Difficulty escalation monotonicity across waves 1-40 (bounded).
 // 4. MIRV step-unlock threshold.
 // 4b. MIRV split-zone geometry (top-third once, top-third + halfway from wave 8).
+// 4c. MIRV child speed multiplier (slower right at introduction, ramps to full speed).
 // 5. Scripted explosion/collision fixture.
 // 5c. Bonus plane fixture (unlock wave, crossing speed, hit/score/debris).
 // 5d. Bonus UFO fixture (unlock wave, weaving/shots, hit/score/debris).
@@ -16,7 +17,7 @@
 
 import {
   BASE_SLOTS, CITY_SLOTS, GROUND_SLOTS, HEIGHT, WIDTH, GROUND_Y, slotX, mulberry32, pickCities,
-  DEFAULT_CITIES, TUNE, spawnInterval, fallSpeed, waveQuota, mirvChance,
+  DEFAULT_CITIES, TUNE, spawnInterval, fallSpeed, waveQuota, mirvChance, mirvChildSpeedMult,
   PALETTES, paletteIndexForWave, createGame, step, pickFiringBase,
   fireInterceptor, lerpPos, explosionRadius,
 } from '../src/games/coloradodefense/ColoradoDefenseLogic.js';
@@ -183,6 +184,41 @@ console.log('MIRV split-zone geometry');
   check('its second split is scheduled in SPLIT_ZONE_2', sawZone2SplitY);
 }
 
+// ── 4c. MIRV child speed multiplier ─────────────────────────────────────────────
+
+console.log('MIRV child speed multiplier');
+{
+  check('multiplier at MIRV_WAVE is exactly the base value',
+    mirvChildSpeedMult(TUNE.MIRV_WAVE) === TUNE.MIRV_CHILD_SPEED_MULT_BASE);
+  let monotonic = true;
+  for (let w = TUNE.MIRV_WAVE + 1; w <= TUNE.MIRV_WAVE + 20; w += 1) {
+    if (mirvChildSpeedMult(w) < mirvChildSpeedMult(w - 1)) monotonic = false;
+  }
+  check('multiplier is monotonic non-decreasing with wave', monotonic);
+  check('multiplier never exceeds MIRV_CHILD_SPEED_MULT_MAX',
+    mirvChildSpeedMult(TUNE.MIRV_WAVE + 20) <= TUNE.MIRV_CHILD_SPEED_MULT_MAX);
+  check('a +0.5/wave growth step reaches the max within one wave of introduction',
+    mirvChildSpeedMult(TUNE.MIRV_WAVE + 1) === TUNE.MIRV_CHILD_SPEED_MULT_MAX);
+
+  // A child spawned at the reduced multiplier takes proportionally longer to
+  // cover the SAME distance as one spawned at full speed. Force rng()=0
+  // before each call so pickTargetSlot() deterministically picks the same
+  // target both times — otherwise a different target/distance would
+  // contaminate the dur comparison.
+  const sim = createGame(DEFAULT_CITIES, 60);
+  sim.wave = TUNE.MIRV_WAVE;
+  const from = { x: 500, y: 400 };
+  sim.rng = () => 0;
+  const full = sim.spawnEnemyMissile(from, false, 1);
+  sim.rng = () => 0;
+  const slow = sim.spawnEnemyMissile(from, false, mirvChildSpeedMult(sim.wave));
+  check('a slowed child (same distance) takes longer to arrive than a full-speed one',
+    slow.dur > full.dur, `full=${full.dur} slow=${slow.dur}`);
+  check('the slowdown ratio matches the configured base multiplier',
+    Math.abs(full.dur / slow.dur - TUNE.MIRV_CHILD_SPEED_MULT_BASE) < 1e-6,
+    `ratio=${full.dur / slow.dur}`);
+}
+
 // ── 5. Explosion/collision fixture ────────────────────────────────────────────
 
 console.log('Explosion/collision fixture');