This is very neat but gamepad mapping can't be configured and the browser default "standard" mapping doesn't work very well (at least with my Xbox one controller).

If you visit chrome://flags you can enable "Restrict gamepad access" which will disable the default controller's mapping.

Incidentally, I recently wrote a small crossplatform gamepad mapper you can use: https://github.com/framp/joystick-mapper/releases/tag/0.3.0

Configuration for psxparty here: https://github.com/framp/joystick-mapper/blob/master/example...