Level 4 — Molten Nest: Magma King boss

[cmalpass]

What

The endgame level: a short, climactic lava run ending in a pattern-based boss fight against the Magma King.

Boss (src/boss.ts)

• Patrol inside the arena, telegraphed 3-glob magma spreads (0.75s glow + warning), and telegraphed charges (0.85s crouch, screen shake, 640 px/s) that stagger the king when he hits the arena walls (2.2s)
• Orb mechanic: 3 crystal orbs on perches around the arena — shattering all 3 stuns the king (3.2s); shattered orbs respawn
• Damage: stompable only while staggered/stunned (200 pts, bounces); armor clanks otherwise; side contact deals 1 hit (i-frames respected); magma globs are dodgeable
• Defeat: 3 stomp hits → 1.6s death sequence, ember burst, onBossDefeated (fires exactly once), +1500

Level 4 "Molten Nest"

• Lava-pit approach, walled boss arena (both walls have walk-under entry gaps), orb perches, and a nest gate that latches open only on boss defeat — the nest is unpassable until the king falls
• 3 hidden fossils, 14 crystals, checkpoint, beetle, theme-specific palette + "THE MAGMA KING SLEEPS IN THE NEST." intro

Polish

• Magma glob projectile type + ember particles + boss roar/orb SFX
• HUD: boss HP bar (top-right) with 3 orb pips
• Victory ceremony: "THE MAGMA KING FALLS!" title, molten confetti, "Magma King defeated! +1500" results line
• Menu: 5th level card "MOLTEN NEST — The Magma King's arena"

Validation

• typecheck ✓ · 174/174 tests (10 files; +14 boss, +8 LEVEL_4 integrity, +2 integration) ✓ · build 124 kB / 38 kB gzip ✓ · lint ✓
• Headless E2E: menu (5 cards) → Molten Nest → boss patrol → defeat (gate latches, status "THE MAGMA KING FALLS!") → victory ceremony; zero page errors; screenshots verified
• CI note: GitHub CI fails on this repo for pre-existing unrelated reasons; local validation is the merge gate.

Part of the Batch B "Endgame" plan (boss → power-ups → adaptive music).