Implemented the help button and first-visit rules overlay with Close, Escape and keyboard focus support. Game logic, wallet flow, contracts and CSP remain unchanged.

Production export and docs are included. Build, typecheck and Chromium checks passed. WebKit was unavailable; lockfiles were left untouched as required. Nothing was fabricated.

Validation and limitations

Not delivered: artifacts/accessibility.json, artifacts/interactions.json, artifacts/preservation.json, artifacts/screenshots/1440-game.png, artifacts/screenshots/1440-help.png, artifacts/screenshots/320-game.png, artifacts/screenshots/320-help.png, artifacts/screenshots/390-game.png and 3 more. Under artifacts/, only this step's named outputs leave the machine.

I found two problems in the "How to play" overlay: one medium bug and one low fidelity issue. All seven requirements in the brief are met, and none is missing or faked.

Area	Count
Brief requirements	7: 7 met, 0 missing, 0 faked
Broken features	1 (medium: after the overlay closes, Space reopens it instead of dropping a hamster)
Game on the first screen at 390	Yes: the wheel and DROP are visible once the overlay closes
taste@1 checks passed	11 of 16 (the 5 that failed all come from the existing design, which the brief says to keep)
Copy findings	0
Share card	Present: title, favicon, og:title, og:image, description

Requirements

• "small 'How to play' button in the top bar": met, #howToPlay in index.html:24, 99×44px at top right at 390.
• "opens a short overlay with the rules": met, <dialog id="playHelp"> in index.html:103, which lists five rules:
  • "drop hamsters into the turning wheel": met, index.html:106.
  • "two neighbours of the same level merge into the next level": met, index.html:107.
  • "merges add time to the timer": met, index.html:108.
  • "a completed Squeekchain block gives a joker": met, index.html:109.
  • "Live mode follows the real Squeekchain wheel speed": met, index.html:110.
• "closes with a button or the Escape key": met, #closePlayHelp and the Escape handler in how-to-play.js:46. I tested both in Chromium.
• "matches the current look": met, with one low finding. The dialog uses the site's own colours, heading style and button style, but the trigger button is mixed case.
• "shown automatically on the first visit only": met. It is remembered in local storage, falls back to session storage, and does not show after a reload (tested).
• "Keep everything else exactly as it is": met in the files, but behaviour changed:
  • main.js, app.css and decor.js are byte-identical to the previous commit.
  • The Content-Security-Policy is unchanged.
  • There are no new external hosts. The probe saw only api.squeekchain.com and the Sepolia RPC, as before.
  • The one behaviour change is the Space key, finding 1.

Findings (written to .imd-findings.json)

1. Medium, bug: how-to-play.js:35 sends focus to the "How to play" button whenever the overlay closes. The game ignores keys pressed while a button has focus, so a new player's first Space press reopens the rules instead of dropping.
   • Measured at 390 in Chromium: after Escape, the overlay is open again after Space and the timer still reads 30.0. After clicking the page background, Space drops and the timer reads 29.6.
   • Fix: return focus to the button only when the button opened the overlay. After the automatic first-visit overlay, clear focus instead.
2. Low, fidelity: how-to-play.css:10-11 turns off the site's button styling for the trigger. It is the only lowercase, untracked button; every other button, including this overlay's own CLOSE button, is uppercase at 0.12em.
   • Fix: delete those two lines.

The five probe failures I did not report: uppercase labels, wide letter spacing, label-above-heading pairs, monospace prose, and 140 words of prose at 1440. All five are in the existing game design, which the brief says to keep exactly as it is.

WebKit was not tested. Playwright's WebKit would not launch on this machine because system libraries are missing, so the overlay is checked in Chromium only.

The idea: a dark arcade panel game built around one dotted, turning hamster wheel, with LED title type. The overlay adds no new visual element.