Build a representative matrix
Pick one current desktop browser, a second engine, and a narrow mobile viewport if touch play is part of the design. Add a tablet or a branded browser only when usage or a known dependency makes it relevant. Playwright can run projects across Chromium, Firefox, and WebKit, and its documentation explains that the bundled browser builds and operating-system media support can differ. Treat this as useful engine coverage, not a guarantee of identical results on every consumer browser.
Test input and layout at meaningful sizes
Check keyboard and pointer controls separately. Confirm that keys do not scroll the page unexpectedly when they should control play, and that pointer targets remain large and separated enough for the intended interface. Resize the viewport and look for cropped instructions, hidden controls, or a game area whose visual scaling changes collision expectations. A responsive canvas can look correct while its coordinate mapping still uses the old dimensions.
Questions about game cross-browser testing
Which browsers should I test a browser game in?
Choose environments based on audience and technical risk. A representative set across browser engines and a mobile viewport is a useful start, but it cannot guarantee every device combination.
Does passing Playwright WebKit tests prove Safari compatibility?
It provides WebKit coverage, but Playwright notes that its WebKit build can differ from branded Safari and platform media support varies. Test actual target environments when those details matter.