CIWS Command

A Missile Command–style game where, instead of firing exploding interceptor bursts, you defend your cities with CIWS (Close-In Weapon Systems) — rapid-fire gun mounts that spray a stream of tracer rounds. The belt feed is endless, but rounds arc and slow with distance, so you still have to lead your targets.

Rendered in WebGL (Three.js) with bloom for a neon look, while the gameplay stays a flat 2D plane viewed nearly head-on.

Play

▶ Play it in your browser — hosted free on GitHub Pages (auto-deploys from main). To run locally:

python3 serve.py 8011      # or: bun run serve
# then open http://localhost:8011

serve.py is a tiny static server that sends no-cache headers (so edits always show up). Or use the ciws config in .claude/launch.json with the preview tooling.

Tests

Game logic has a unit suite run with Bun (no dependencies):

bun test          # or: bun run test

It covers utils, physics, the entities (ballistics, drag, MIRV split, interceptor boost/coast/energy), the weapon systems, the high-score table, the save checkpoint, and the Game orchestration (waves, spawning/threat gating, collisions & HP, bounties, impacts and nuke air-bursts, bombers, the autonomous launcher and laser, the economy, the shop, and win/lose conditions).

The simulation is headless-testable because the WebGL renderer is injected into Game rather than imported — see the architecture note below.

For hands-on testing there is also a hidden dev console: press ` (backquote) in any state. It offers god mode (cities & gun invincible) and endless single-threat sandboxes (loop bombers, drone swarms, nukes, etc.) for observing enemy and autonomous-weapon behaviour in isolation. Dev runs are marked with a DEV badge and never touch the high-score table.

Controls

Input	Action
Mouse move	Aim the CIWS — it fires on its own while threats are inbound
Space (in play)	Call the F-16 airstrike (when a strike package is racked)
Touch (mobile)	Drag on the fire-control pad below the field — a radar repeater with absolute aim mapping, so your thumb never covers the action (touching the field directly also aims). An on-screen F-16 STRIKE button appears above the pad while a package is racked
P	Pause / resume
R	Restart
M	Mute / unmute
Space / click	Deploy from the tutorial screen / restart after game over (with a saved run, Space continues it)

You aim; everything fires itself. The CIWS shoots wherever you point it (and holds fire when the sky is clear), interceptors launch themselves at distant high-value threats, and the laser handles whatever gets close. A tutorial screen at the start covers all of this in-game.

Weapons

• CIWS gun — a single central rapid-fire gun with an endless belt feed that fires automatically while threats are inbound; you steer the stream with the mouse and must lead targets. One tracer kills a standard RV. If a warhead ever hits the gun, you instantly lose — so anything heading for the centre is top priority.
• Interceptors (autonomous) — an armory purchase that fields homing anti-missiles with unlimited stock, gated by a reload cooldown (6s at the start; shop upgrades buy it down to 1s); the pod comes back fully loaded each wave. The launcher fires itself at the highest-value, most distant threat — it never engages cheap clutter (drones and glide bombs are the laser's and gun's business, though a blast can still catch one), can't see cloaked stealth, and won't shoot inside its minimum engagement distance. Missiles cold-launch straight up from a THAAD-style truck — guidance stays locked for the first ~100px of climb — then turn onto an intercept course — but coasting flight bleeds energy, hard turns scrub extra speed, and a round that drops below maneuvering speed self-destructs: some intercepts genuinely run out of energy. If the target dies en route the missile retasks onto the nearest valid threat (or self-destructs), and it detonates with an area blast.
• Laser (shop upgrade) — a fully autonomous beam emplacement left of the gun with a trainable emitter head. It picks the lowest visible threat in range (anything that flies — cloaked stealth excepted; armoured targets just take a longer, committed burn), physically slews onto it, and only then burns it down over time. It can't depress below ~5° above the horizon, so only the lowest deck-skimmers slip under its arc. Output falls off with distance — full power up close, weaker out toward its maximum range, beyond which it can't latch at all. After each kill it recharges (~5s, upgradable to ~1s).
• F-16 airstrike (once per wave) — the panic button. Buy a strike package in the armory, then press Space mid-wave (or tap the on-screen STRIKE button on mobile) and one F-16 per two visible enemies scrambles, each carrying two air-to-air missiles — one AAM per enemy, except nukes and unsplit MIRV-nuke buses, which count as two enemies and draw a pair of missiles from two different jets (two hits exactly crack a MIRV-nuke bus). Every jet flies its own intercept solution: it pairs two x-neighbouring targets, runs in from the side far from them (a close-side entry would over-fly the pair before the rail is in parameters), enters at the altitude the pair is predicted to occupy when it reaches firing range, then pitches its nose onto each target line (pitch authority and turn rate limited — within reason) and fires straight off the nose once the target is in range and the nose is on the line — so the flight can swarm from both sides at once, announced by a sonic boom and an "Engaging hostiles" radio call. AAMs fly the same honest guidance as interceptors — smaller, born fast, with the seeker live immediately (no cold-launch climb gate) and the interceptor's solid-motor plume at reduced scale (the jets themselves fly clean) — but turn-rate-limited and energy-bleeding, so they can still miss a hard-jinking target. One package in the rack at a time; an unused package carries over to the next wave. Calling it on an empty sky is denied (the package is kept).

Economy & shop

You earn credits (separate from score) from several sources, shown as a breakdown on the wave-clear screen:

• Kill bounties, scaled by threat type — standard/drone/glide-bomb 1, evasive 2, hypersonic/cruise 3, MIRV carrier/stealth/bomber 4 (split MIRV children pay the standard rate), MIRV-nuke bus 10 (its released warheads 5 each), nuke 12.
• All-clear bonus for destroying every enemy that wave (nothing leaked).
• Cities saved — per surviving city.

Between waves the intermission becomes an armory — click an item (or press its number), hover any row for a fuller explanation, then NEXT WAVE / Space to continue. Every ladder runs deep enough to soak late-game credits:

Item	Effect
Interceptor Battery / Reload	Field the auto-launcher, then shorten its cooldown, 6s → 1s (multi-level)
Gun Shield / Shield Recharge	Fit a dome on the CIWS that absorbs one warhead, then buy down its recharge (multi-level)
Laser Turret / Laser Recharge	Buy the autonomous beam, then speed its recharge (multi-level)
Upgrade Fire Rate	Faster CIWS cycle rate (7 levels — each compounds on the last)
F-16 Strike Package	One airstrike in the rack; Space calls it mid-wave (unused packages carry over)

The Gun Shield (a regular shop item) fits a dome over the CIWS that intercepts one warhead on contact — the missile detonates against the dome instead of the gun — then fails with a burst and recharges (~10s, upgradable down to ~2.5s via Shield Recharge levels). Cities can't be shielded; the dome is how you survive a hit that would otherwise instantly end the run.

There are no city repairs — a lost city is gone for the run, taking its end-of-wave income with it.

Prices, amounts and earnings live in config.economy, config.shop, and config.shield.

Rules

• 6 wide cities cluster around a single central CIWS gun — flanked, once bought, by the laser emplacement (left) and the THAAD launcher truck (right; the next missile's tip pokes from the pod whenever a launch is ready). Most threats rain from the top; cruise missiles, drone swarms and bombers sweep in from the edges.
• The gun tracks the mouse. Rounds disperse in a small cone, so closer, well-led shots land more reliably. One hit destroys a standard missile.
• A missile reaching the ground blasts everything within its radius — a hit anywhere on a city's footprint counts, not just dead centre. Lose all cities, or take a single hit on the central gun, and it's game over — unless a shield bubble is up to absorb it (see the shop).
• Enemies are programmed against structures that are alive or fell earlier this same wave (their salvo was targeted before the city dropped); from the next wave on, known rubble draws no fire. About a third of all shots miss into the gaps regardless.
• Clearing a wave awards bonuses for surviving cities, and the interceptor launcher and laser come back fully charged.
• Game over shows a local high-score table (top 10, stored in localStorage) with your run highlighted. Scores are stamped with a balance version (BALANCE_VERSION in scores.js): a rebalance bumps it, which hides every older entry — scores from a different balance aren't comparable — without deleting them from storage.
• Progress is checkpointed in localStorage whenever a wave is cleared — before any armory spending, so a closed tab isn't a lost run: the menu offers CONTINUE (resume at the armory before the saved wave — upgrades, credits and rubble intact, shopping never skipped) or NEW GAME (forfeits the save). A reload after shopping simply refunds those purchases to re-pick; the next wave clear banks them. Game over deletes the checkpoint — defeat is final. Dev-console runs (sandbox / god mode) never touch it.

Threats

Threat	Appears	Behaviour
Standard RV (red)	wave 1+	Straight dive toward a structure; 1 hit
Drone swarm (gray, squat)	wave 2+	Five low gliders from one screen edge (counts as one wave slot), each with its own target; 1 hit each
Evasive RV (purple)	wave 2+	Fast (1.35× base) and jinks with real maneuvering physics: a constant-g lateral pull that reverses on an irregular timer, carving banked S-turns inside a bounded leash; 1 hit
MIRV bus (green, large)	wave 3+	Armoured (3 hits); splits into red RVs at altitude
Cruise missile (gold)	wave 3+	Enters from a screen edge at low altitude, pops up, then dives; 2 hits
Bomber (bronze, Su-27 silhouette)	wave 4+	Crosses fast at mid altitude dropping 2–3 glide bombs (1 hit each — yes, you can shoot down glide bombs; real ones get intercepted too). The pilot flies defensively: he weaves whenever a homing round is hunting him or his own decoy, punches out flare bursts that can seduce the seeker, pulls high-g S-breaks when the round closes, and weaves out of incoming CIWS streams — all under honest energy physics (total speed stays near cruise; a pull pitches the flight path, it doesn't add free velocity). Forcing a bomber to jink aborts its bombing run for good — suppression is a mission kill. About 40% survive a full defensive engagement. Killing the bomber pays 4 but it exits without leaking if you let it go; 3 hits
Hypersonic (orange dart)	wave 4+	Very fast and barely slows in the dense air; 1 hit but hard to track
Stealth cruise (pale, ghostly)	wave 6+	Flies the cruise profile cloaked — invisible, silent, no lock-on, no laser — until its pop-up; a blind CIWS sweep can still clip it; 2 hits
Nuke (crimson, huge)	wave 5+	Announced by a klaxon and a "Nuclear launch detected" voice; never the first or last threat of a wave, and the per-wave cap keeps climbing in later waves (one at wave 5, two at 8, three at 11...). Full ballistic speed and heavily armoured (30 hits — a single interceptor barely dents it). Targets inner cities and air-bursts above them, leveling the target and both neighbours — including the CIWS if it's next door — then a mushroom cloud climbs
MIRV nuke (hot pink, huge)	wave 9+	The very-late-game capstone, with its own warning voice. The bus comes in 1.5× faster than a nuke but far less armoured (10 hits) — kill it before the split and the whole attack dies. Let it split and three small warheads fan out onto three different cities, each a fast little air-bursting nuke (3 hits, smaller yield: it levels only the city under it)

A non-killing hit on the armoured MIRV flashes it white with a metallic ting — chip it down with the gun, or pop the whole bus with one interceptor before it splits. Missile speed is constant across waves (~190 px/s base); difficulty ramps via missile count, spawn cadence, and the threat mix, not speed.

Per-type hit points live in config.missile.hp and are fully tunable.

Physics

A simple shared atmosphere (physics.js) governs everything that flies. Air is thin up high and dense near the ground (density decays exponentially with altitude), and quadratic drag scales with that density and with speed:

• CIWS rounds feel gravity and drag — they slow and arc, so long shots need lead (the gun is genuinely close-in). A round burns out once it slows below a threshold speed: a straight-up burst just reaches the top of the field and dies near apogee, while a flat shot keeps flying its whole arc — still lethal on the way down.
• Enemy missiles feel drag only (no gravity, so they still track their target) — they decelerate as they sink into denser air, giving you more time to engage them low.
• Interceptors fly a real two-phase profile: a powered boost (with a rocket-engine roar) that accelerates them to top speed, then an unpowered coast where gravity and drag bleed off energy while they keep steering. Their turn rate and acceleration are limited, so they reliably kill slow/ straight threats but can overshoot and miss fast ones — late-game hypersonics in particular will sometimes outrun them.

Tunables live in config.physics (gravity, scale height, per-projectile drag). The play field (config.world) is deliberately large so there's plenty of air.

Architecture

Vanilla JS + Canvas/WebGL, no build step. Three.js is vendored locally under vendor/three/ (resolved via the import map in index.html), so the game runs fully offline.

File	Responsibility
index.html / style.css	Import map + layered canvases (WebGL scene, 2D HUD)
js/config.js	All tunable values — balance the game here
js/strings.js	All user-facing text — menus, HUD, armory copy
js/utils.js	Math helpers (clamp, rand, distance, array culling)
js/physics.js	Altitude-based air-density model + quadratic drag helper
js/entities.js	City, Turret, Bullet, EnemyMissile, Interceptor (also flies the AAM), FriendlyJet, Flare, Particle (data + update, no draw)
js/weapons.js	CIWSWeapon, InterceptorWeapon, LaserWeapon, AirstrikeWeapon — stats, upgrades, fire logic
js/scores.js	Local high-score table (localStorage, injectable for tests)
js/save.js	Run checkpoint save slot (localStorage, injectable for tests)
js/audio.js	Procedural Web Audio SFX + speech announcements (singleton sfx)
js/renderer3d.js	Renderer: Three.js scene, bloom, GPU buffers, projection
js/game.js	Game: state machine, waves, input, simulation, 2D HUD
js/main.js	Canvas wiring + rAF loop + frame-rate quality governor
vendor/three/	Pinned Three.js r160 core + postprocessing addons
serve.py	No-cache static dev server
tests/	bun test suite + setup/helpers

Dependency injection: main.js constructs the WebGL Renderer and passes it into new Game(hudCanvas, renderer). Game never imports the renderer (or Three.js), so the whole simulation loads and runs headlessly under bun test with a stub renderer. Audio is likewise inert until a user gesture calls sfx.unlock(), so it needs no stubbing in tests.

Separation of concerns: the simulation runs in a fixed virtual resolution (config.world, default 1400×1350) so balance — distances, speeds, gun spacing — never depends on the window size. The camera frames that field edge-to-edge vertically at any window aspect; on wide monitors the HUD docks into the spare columns beside the field (and collapses into corner overlays on narrow ones). renderer3d.js maps sim space to 3D world space, draws everything as emissive neon with an UnrealBloom pass, and exposes screenToWorld / worldToScreen so input and the HUD overlay stay aligned with the tilted camera. The HUD, menus and shop are drawn in screen space on a 2D canvas. Entities carry no draw code — the renderer reads their fields.

License

MIT (see LICENSE). Three.js is vendored under vendor/three/ and carries its own MIT license.

Roadmap

This is the foundation for a broader missile-defense game. Natural next steps:

• More weapon systems on the weapons.js abstraction (e.g. flak bursts, long-range area-denial interceptors) and more shop upgrades.
• More threat variety: saturation salvos, decoys, jamming.
• Deeper economy: persistent upgrades across runs, city armour, etc.
• A music bed and an online leaderboard.