Marble Madness: six courses in 3D

🎱 CLAUDE OPUS 5.5 - one-shot game! Marble Madness is back — and it's free, in your browser, with nothing to download. Six floating courses. Real 3D graphics. Physics that behave like an actual rolling glass marble. Pistons, acid pools, launch pads, icy chutes, black steel balls, a pinball funhouse, and a final Gauntlet where you have to duck into an alcove while a steel ball rolls at you. The part that still blows my mind: it was built in ONE shot. Claude Opus 5.5, working in Claude Code, got a single short request — "analyze this old 2D version and write a better one" — and came back with all six levels, the physics engine, the graphics, the sound and the menus, rewritten from scratch. No assets. No image files. No audio files. One HTML file, ~2,700 lines, ~145 KB. Graphics: three.js on WebGL, real-time shadows and reflections, glow, sparks, confetti, shattering glass. Every texture — the tiles, the swirl inside the marble — is drawn by code at startup. Sound: music and SFX synthesized live with the Web Audio API, including a rolling sound that tracks the marble's speed. Physics: solved 240 times per second. Gravity follows the actual slope under you, momentum carries, walls bounce, and a fall of more than ~3 steps shatters you. The ground you see IS the surface the physics uses — so curved bowls and wavy floors do exactly what they look like they'll do. And instead of hoping the levels were beatable, the AI wrote an autopilot that drove the marble through every course inside the real game, verified each jump lands safely, confirmed each hazard kills when it should and only then, and set the par times from those runs. Even the 15-second promo video was rendered frame by frame from the live game, with captions and a soundtrack composed in code. Since launch it's had only small quality-of-life touches: mouse "point mode" (the marble rolls toward your cursor, farther = faster, point at it to brake), a two-finger trackball mode that mirrors the original arcade cabinet, gamepad support, touch steering, and a clearer lift on Sky Islands with status lights and a glowing shaft. There's a two-player race mode on one screen: arrows vs WASD, first marble in the goal wins. Stars, best times and unlocks save right in your browser. Free. No account, no ads, no install. Chrome, Safari, Edge, Firefox — desktop, tablet, phone. Play it 👉 Link in comments (Unofficial non-commercial fan tribute to the 1984 arcade classic. Marble Madness is a trademark of its respective owner.) #MarbleMadness #BrowserGame #AI #Claude #WebGL #RetroGaming