Kiln Run

Build a tiny browser game called "Kiln Run".

Game spec
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A glaze firing you schedule by hand across a twelve-hour curve. The kiln chart shows the required recipe as a ghost line — ramp up, hold a bisque plateau, climb to peak, then a slow controlled cool — and you set the burner setting each minute with the arrow keys, click the throttle lever, or drag the on-screen slider. Too fast and the glaze crazes and the pot cracks; too slow and it never matures and stays matte; overshoot the peak and the piece melts to the shelf. The thermocouple reading lags the burner by a few seconds and the kiln has thermal mass, so early throttle has to be pulled back before you see the effect — that lag is the whole game. Live readouts: chamber temperature, minutes remaining, glaze maturity percentage and a crack meter. A finished piece pays by maturity accuracy, surviving cracks and how tight you tracked the ghost curve, then the next firing has a steeper recipe and a lumpier kiln. Kiln-room look: firebrick wall, a glowing peephole that brightens with temperature, a graph-paper chart with a plotting pen, and a low burner rumble in WebAudio that rises with the throttle.

Hard constraints — the game will be embedded in a sandboxed iframe on a static gallery site, and a headless browser will screenshot it:

1. Output exactly ONE self-contained HTML file. All CSS and JS inline. Zero external requests: no CDNs, no external fonts, images, or sounds, no fetch/XHR/WebSocket. Any sound must be synthesized with WebAudio.
2. The iframe sandbox is "allow-scripts allow-pointer-lock" (plus an autoplay permission). So: no localStorage, cookies, or indexedDB (opaque origin — access throws); no popups, window.open, or navigation; no access to the parent page; alert()/prompt()/confirm() are silently blocked.
3. The playfield must be visible within 800 ms of load — that is when the screenshot is taken. No dead white screen. If there is a start screen, make it visually rich.
4. Controls: keyboard AND mouse must both work, plus on-screen touch buttons for phones. Call preventDefault() on game keys (arrows, space) so the page never scrolls.
5. The view is 16:9 and must scale to fill the viewport with no overflow or scrollbars.
6. Show a visible score. If the genre has a losing state, show a game-over screen with a restart (button and a key). Idle/clicker games skip game over but still need clear numeric feedback.
7. If you track a score, report it to the arcade shell so the player's best is remembered between visits: on every score change, call parent.postMessage({ source: "ai-arcade", type: "score", score: <number> }, "*"). It is safe to call it no matter what the parent does with it.
8. Keep it tiny: aim for under 400 lines, 60 fps, no frameworks. That 400-line target does not apply to 3D games — true 3D (a camera and perspective-projected world) or pseudo-3D (projected road/track, depth-sorted sprites) — which need their own software renderer and typically land at 800–1400 lines. The rest of this constraint still binds every game: 60 fps, no frameworks, no external assets, and no padding to reach a length.
9. Difficulty: the arcade shell passes the player's chosen difficulty as a URL query parameter. Read it with new URLSearchParams(location.search).get("difficulty") — the value is "easy", "medium", or "hard" (missing or unknown means "medium"). Make the three levels meaningfully different — speed, lives, enemy pressure, reaction time, whatever fits the genre; clicker/idle games with no losing state use starting resources and upgrade cost curves instead. Show the active level in the HUD. Without the parameter the game must be fully playable at its default (medium) tuning.

Return only the complete HTML file, no commentary.