diff --git a/.github/scripts/test-autoplay.js b/.github/scripts/test-autoplay.js
index e980bed..b4fd009 100644
--- a/.github/scripts/test-autoplay.js
+++ b/.github/scripts/test-autoplay.js
@@ -1,4 +1,4 @@
-const { chromium } = require('playwright');
+const playwright = require('playwright');
 
 const CONFIG = {
   error: { overlaySelector: '#site-error', clickSelector: '#site-error button', initialTitle: 'Internal Server Error' },
@@ -7,11 +7,16 @@ const CONFIG = {
 
 const overlayType = process.argv[2];
 if (!CONFIG[overlayType]) {
-  throw new Error(`usage: node test-autoplay.js <${Object.keys(CONFIG).join('|')}>, got "${overlayType}"`);
+  throw new Error(`usage: node test-autoplay.js <${Object.keys(CONFIG).join('|')}> [chromium|firefox|webkit], got "${overlayType}"`);
 }
 const { overlaySelector, clickSelector, initialTitle } = CONFIG[overlayType];
 const cookieSelector = '#cookie-banner';
 
+const browserType = process.argv[3] || 'chromium';
+if (!playwright[browserType]) {
+  throw new Error(`unknown browser engine "${browserType}", expected chromium, firefox, or webkit`);
+}
+
 async function waitFor(page, predicate, { timeout = 5000, interval = 100 } = {}) {
   const start = Date.now();
   while (Date.now() - start < timeout) {
@@ -22,7 +27,7 @@ async function waitFor(page, predicate, { timeout = 5000, interval = 100 } = {})
 }
 
 (async () => {
-  const browser = await chromium.launch();
+  const browser = await playwright[browserType].launch();
   const page = await browser.newPage();
   await page.goto('http://localhost:8080/', { waitUntil: 'load' });
 
@@ -102,7 +107,7 @@ async function waitFor(page, predicate, { timeout = 5000, interval = 100 } = {})
     throw new Error('expected the cookie banner to be hidden after clicking, but it is still visible');
   }
 
-  console.log(`OK: ${overlayType} overlay + cookie banner shown, video autoplays muted, and clicking unmutes + hides both`);
+  console.log(`OK (${browserType}): ${overlayType} overlay + cookie banner shown, video autoplays muted, and clicking unmutes + hides both`);
   await browser.close();
 })().catch((err) => {
   console.error(err);
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index e4b5c0a..82a34bb 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -161,7 +161,11 @@ jobs:
         run: |
           npm init -y >/dev/null
           npm install --no-save playwright@1
-          npx playwright install --with-deps chromium
+          # Firefox gets its own engine check alongside Chromium - it's
+          # historically the most divergent on autoplay/gesture policy
+          # enforcement of the mainstream browsers, so a bug that's fine
+          # under one can still be broken under the other.
+          npx playwright install --with-deps chromium firefox
 
       - name: Start container with OVERLAY=error
         run: docker run -d --name rickroll-error -p 8080:8080 -e OVERLAY=error rickroll:test
@@ -175,8 +179,11 @@ jobs:
           docker logs rickroll-error
           exit 1
 
-      - name: Verify site-error + cookie banner autoplay muted and unmute on click
-        run: node .github/scripts/test-autoplay.js error
+      - name: Verify site-error + cookie banner autoplay muted and unmute on click (Chromium)
+        run: node .github/scripts/test-autoplay.js error chromium
+
+      - name: Verify site-error + cookie banner autoplay muted and unmute on click (Firefox)
+        run: node .github/scripts/test-autoplay.js error firefox
 
       - name: Stop OVERLAY=error container
         if: always()
@@ -194,8 +201,11 @@ jobs:
           docker logs rickroll-loading
           exit 1
 
-      - name: Verify loading-screen + cookie banner autoplay muted and unmute on click
-        run: node .github/scripts/test-autoplay.js loading
+      - name: Verify loading-screen + cookie banner autoplay muted and unmute on click (Chromium)
+        run: node .github/scripts/test-autoplay.js loading chromium
+
+      - name: Verify loading-screen + cookie banner autoplay muted and unmute on click (Firefox)
+        run: node .github/scripts/test-autoplay.js loading firefox
 
       - name: Stop OVERLAY=loading container
         if: always()
diff --git a/scripts/index/80-index.sh b/scripts/index/80-index.sh
index 5ef86d3..4987921 100644
--- a/scripts/index/80-index.sh
+++ b/scripts/index/80-index.sh
@@ -335,7 +335,17 @@ tee /usr/share/nginx/html/index.html << EOF >/dev/null
                 }
             }
 
-            var events = ['click', 'keydown', 'touchstart', 'pointerdown'];
+            // click fires for both a genuine mouse click and, on
+            // touch devices, the synthetic click a browser dispatches
+            // after a completed tap - deliberately not touchstart or
+            // pointerdown, which fire the instant a finger touches the
+            // screen, before the browser even knows it's a tap and not
+            // the start of a scroll/drag. WebKit in particular doesn't
+            // treat those as a strong enough gesture to permit unmuted
+            // playback, so play() silently gets rejected and the
+            // click that follows never gets a retry since the
+            // listeners here are already torn down.
+            var events = ['click', 'keydown'];
 
             function reveal() {
                 video.muted = false;