One prompt, one game — the second run

Same prompt, same effort level, same output cap, same machine. GLM-5.3 got the identical brief that Claude Fable 5.1 got, and built something completely different: an exploration game instead of a shooter. 27 minutes, first try.

VESPERA — title screen: monolith under an aurora, two moons, a crashed lander

The title screen. The key art behind it was generated during the run.

▶ Play VESPERA

13.9 MB, one file, everything embedded. WASD move · mouse look · Shift sprint · Space jump · E seal. Sound is on — press M to mute. Give it a moment on first load, the 3D scene is 7 MB of geometry.

The numbers, side by side

	Fable 5.1 · GLM-5.3
Wall clock	24.2 min · 27.3 min
Turns	75 · 146
Cost	$9.90 · $9.39
Output tokens	95,832 · 106,966
Rounds to green	1 · 1
Single file size	4.4 MB · 13.9 MB

Both ran at effort high with a 64,000 output-token cap, against the same gate, on the same RTX 5090.

What GLM-5.3 built

VESPERA · The Long Dusk. Your lander went down at dusk and the stardrive shattered into eight shards across the valley. Collect them and seal them at the monolith before night takes the sky — an eight-minute eclipse timer runs the whole game.

Blender 5.2, headless — a 7.1 MB scene: terrain at 51k triangles, the monolith, 8 shards, 46 rocks, 60 plants, a ship wreck and a companion drone. It also exported a 129² height map as JSON so the physics could follow the actual ground instead of faking it.
FLUX.2 Q8 — equirectangular sky (it crossfaded the seam shut), terrain, monolith and hull textures, and the key art above.
LTX-2.5 — a 4-second clip that plays on the monolith's face.
ACE-Step — a 36.7 second beat-aligned loop.
three.js bundled with esbuild, every asset inlined as base64.

Where the two runs met

Both models hit the same trap, and both caught it themselves: the generated music had silence in it. GLM threw away seeds 2201 and 2202, Fable threw away six tracks out of seven. Both found it the same way — by rendering spectrograms and looking at them.

GLM logged one lesson Fable never ran into: call /free on ComfyUI between jobs, or the second load runs out of VRAM at 28.2 GiB.

It verified the finished game the same way too — Playwright driving real Chrome, an autoplay run that collects all 8 shards and reaches the win state, zero console errors.

The prompt

Build a playable 3D game. One self-contained HTML file, game.html, in the
current working directory. Genre and theme are your choice — pick what you can
push furthest. I want quality, not a tech demo.

You have a render workstation. Use it to make the game look like something
nobody built in an afternoon:

- Blender is installed. Model the 3D assets there — props, characters,
  environment pieces, whatever your game needs — and export them for the web.
  Script it, do not click through a UI.
- ComfyUI at http://127.0.0.1:8188, raw API. Generate the textures, skybox and
  any 2D art there. Generate at least one short video clip and place it inside
  the game world where it belongs — a screen, a projection, a hologram.
- Music that fits the world, generated there too, playing in the game.
...

Full text: prompt.txt — byte-identical to the one Fable 5.1 got.