Orbit — Tower Factory Defence

A browser-based incremental tower defence + factory game. Build a refining chain, automate ammo production with conveyor belts, and defend your HQ from escalating waves of enemies. Works on desktop and mobile.

No build step, no dependencies. Just static HTML / CSS / vanilla JS using the Canvas + Web Audio APIs.

Play

Open index.html in any modern browser, or play locally:

git clone https://github.com/MelsomNO/orbit-factory-defence.git
cd orbit-factory-defence
# Either just double-click index.html, or:
python -m http.server 8000   # then visit http://localhost:8000

A tiny static server isn't required — file:// works fine.

How it plays

You start with nothing. Tap & drag ore (◆) from resource nodes onto HQ to bootstrap. HQ refines ore into plates (▣). Convey plates into ammunition plants to produce bullets (●) or missiles (▲). Convey ammo into your turrets.

The full chain:

◆ Node → Harvester → Conveyor → HQ → Conveyor → Bullet Plant → Conveyor → Gun Turret
                                └→ Conveyor → Missile Plant → Conveyor → Missile Turret
                                └→ ⚡ Power Plant → Laser Turret (uses global power)

Turrets each hold up to 10 ammo (more with storage upgrades). Lasers draw from a global ⚡ power pool fed by Power Plants — no ammo belts needed.

Defence

Each round you get a prep timer (60 s for round 1, 25 s between waves) to build and improve your factory. Enemies spawn from the map edge and walk straight at the HQ. If they reach it, they hit HQ HP — let too many through and you lose.

Enemy roster:

🔴 Grunt — 1× HP, 1× speed, 35 HQ damage. Unlocks round 1.
🟡 Scout — 0.45× HP, 1.8× speed, 14 HQ damage. Unlocks round 3.
🟣 Tank — 3× HP, 0.55× speed, 50 HQ damage. Unlocks round 5.
🟤 Brute — 5.5× HP, 0.4× speed, 80 HQ damage. Unlocks round 8.

(HP and damage scale per round on top of these multipliers.)

Buildings

Harvester — auto-mines from a node, pushes ore onto adjacent conveyors.
Conveyor — drag to lay; corners auto-curve, T-junctions auto-form.
Splitter — convert a conveyor tile to split 1 input across 2 outputs (alternating).
Refinery — like HQ but small buffers; useful far from HQ.
Bullet / Missile Plant — consume plates, produce ammo.
Power Plant — adds ⚡ capacity + regen for lasers.
Gun / Missile / Laser Turret — defence.

Upgrades

Each upgradeable building has up to 3 Speed tiers and 2 Storage tiers (missile turret gets Range instead of storage). Upgrades are visible as stars above each building.

Obstacles

Indestructible rocks scatter on the map and grow with each round's expansion. You'll need to route conveyors around them.

Controls

Desktop

Build menu hotkeys — 1–9, demolish X / Delete.
Pause / resume — Space.
Mute / unmute — M.
Cancel tool — Esc.
Pan camera — middle / right mouse drag.
Zoom — scroll wheel.
Reset view — ⌖ button (appears once panned).
Harvest ore — click a node, drag to HQ.
Lay conveyor — select Conveyor tool, drag.
Inspect / upgrade / demolish — click any building, conveyor, or HQ.

Mobile

Single finger: tap to place, tap-and-drag to harvest ore / lay conveyor.
Two-finger drag: pan.
Pinch: zoom.

Tech notes

Canvas 2D for everything — entities, particles, build previews.
Web Audio API for procedural SFX (no audio files).
No build tooling — index.html loads vanilla JS files in dependency order.
All gameplay constants live in js/config.js for easy tuning.

Scoreboard (optional backend)

When your HQ is destroyed you can enter a name to save how many rounds you survived to a shared leaderboard. This needs the little Node + Postgres server in server/. It's entirely optional — open index.html with no server and the game plays exactly as before; the game-over screen just shows Play Again instead of the name form (it detects the backend is missing and degrades gracefully).

Run it

# 1. Postgres: create a dedicated role + database
createuser orbit_game --pwprompt          # choose any password
createdb -O orbit_game orbit_game

# 2. Configure the server
cd server
cp .env.example .env                       # then edit DATABASE_URL with your password
npm install

# 3. Start it (creates the `scores` table on first boot)
npm start                                  # → http://localhost:3000

Now play at http://localhost:3000 (served by the same process) and your scores persist. server/.env is gitignored so your credentials never get committed.

API

GET /api/scores — Top 20 scores, highest rounds first.
POST /api/scores — Body { name, rounds }. Records a score and returns its rank.
GET /api/health — Liveness probe.

Production deploy

In production the static game is served by nginx and /api/ is reverse-proxied to the Node server (kept alive by systemd). The bits that make that work live in server/deploy/:

orbit-scoreboard.service — systemd unit; runs node server.js from server/, restarts on failure, starts on boot. Binds 127.0.0.1 by default (set HOST=0.0.0.0 to expose directly).
nginx-orbit-game.conf.example — nginx server block: serves the repo and proxies /api/ → http://127.0.0.1:3020.

sudo cp server/deploy/orbit-scoreboard.service /etc/systemd/system/
sudo systemctl enable --now orbit-scoreboard
# add the /api/ proxy block to your nginx site, then:
sudo nginx -t && sudo systemctl reload nginx

Set PORT in server/.env to whatever the nginx proxy_pass points at (3020 in the example).

This is a personal-interest project: scores are trusted as submitted, with no anti-cheat. Names are length-capped and HTML-escaped on render; that's it.

File layout

index.html           HUD, intro modal, info panel, game-over + scoreboard
styles.css           layout + responsive HUD
js/config.js         balance numbers, costs, recipes, enemy & upgrade defs
js/state.js          singleton State + Grid lookup
js/world.js          generation: HQ, nodes, obstacles, camera helpers
js/sound.js          procedural sound effects
js/entities.js       placement, factory/conveyor/turret/enemy tick logic
js/render.js         all canvas drawing
js/input.js          unified pointer (mouse + touch), pan/zoom, hotkeys
js/scoreboard.js     game-over name entry + leaderboard (talks to /api)
js/main.js           game loop, HUD updates, info panel, intro
server/              optional Express + Postgres scoreboard backend

Overview