Monsterplex

A Trials-style physics driving game starring a school bus, crossed with Snuggle Truck: land badly enough and the g-force throws your passengers off. Built with Phaser 4, plain ES6 modules, and no package manager.

Running it

Browsers block ES module imports over file://, so serve the folder with any static file server. No install needed - this ships with Python 3:

python3 -m http.server 8000

Then open http://localhost:8000/.

Controls

• Arrow Up / W - throttle
• Arrow Down / S - brake / reverse
• Arrow Left/Right / A/D - lean the bus left/right

Land smoothly or the g-force throws a kid off the bus. Lose all of them and the level fails.

Project layout

index.html            entry point, import map -> vendor/phaser.esm.js
vendor/phaser.esm.js   vendored local copy of Phaser 4 (see below)
src/main.js            Phaser.Game config + scene list
src/config.js          every tunable constant (physics, g-force threshold, camera, ...)
src/scenes/            Boot -> Preload -> Intro -> MainMenu -> LevelSelect (map) -> Play -> LevelScore -> LevelSelect / LevelFailed
src/entities/          Bus, Kid, Terrain
src/systems/           GForceMonitor, KidManager, InputController, CameraRig
src/data/levels/       the 3 hand-authored levels
src/util/              asset manifest, placeholder-texture generator, localStorage progress, small UI helper
assets/                where real art goes (see manifest below) - currently empty

Adding real art

No art assets exist yet - src/util/assetManifest.js lists every image the game expects, and PreloadScene falls back to a synthesized colored placeholder (via src/util/placeholderTextures.js) for anything missing. Drop a real PNG at the exact path below and it's picked up automatically - no code changes needed.

key	path	size	notes
bus_chassis	assets/sprites/bus_chassis.png	170x64	scaled to this size regardless of source resolution
bus_wheel	assets/sprites/bus_wheel.png	52x52	used for both wheels
kid_idle	assets/sprites/kid_idle.png	28x28	passenger while aboard
kid_ejected	assets/sprites/kid_ejected.png	28x28	passenger after being thrown off
bg_far	assets/backgrounds/bg_far.png	256x540	tiled, slowest parallax layer
bg_mid	assets/backgrounds/bg_mid.png	256x540	tiled, mid parallax layer
bg_near	assets/backgrounds/bg_near.png	256x540	tiled, fastest parallax layer
icon_kid	assets/ui/icon_kid.png	24x24	HUD "kids aboard" icon
favicon	assets/favicon.png	32x32	browser tab icon

Tuning the feel

Everything worth tweaking lives in src/config.js, notably:

• GFORCE.ejectThresholdG - how hard a landing has to be before a kid is thrown off. Not physically derived - tune by playtesting.
• GFORCE.gracePeriodMs / ejectCooldownMs - ignore-window after level start/restart, and minimum time between two ejections so one bad landing doesn't empty the whole bus at once.
• BUS.* - suspension stiffness/damping, wheel friction, throttle/lean torque and their clamps.

Set DEBUG = true in config.js to show a live g-force readout and Matter's physics debug overlay in PlayScene.

Phaser 4 loading

Phaser is vendored locally at vendor/phaser.esm.js (downloaded once from jsDelivr's CDN build) and wired up via an import map in index.html, so every source file just does import Phaser from 'phaser' like a normal npm project would - the only place that knows about the vendored file is that one import map line. This keeps the project working fully offline with no runtime dependency on a third-party CDN staying up.

To upgrade Phaser later: download a newer phaser.esm.js build over vendor/phaser.esm.js and re-verify Bus.js against the Matter physics Factory API in the new file (grep for class Factory under the Matter section).