I've updated AVCMS & AV Arcade to display a message and a button when flash is not enabled/installed. This should help with confusion as many browsers are now quietly blocking flash.

To update just upload these two files:

src/AVCMS/Bundles/Games/resources/templates/embeds/flash.twig: http://drop.avscripts.net/KuuY68
src/AVCMS/Bundles/Games/resources/javascript/avcms_games.js: http://drop.avscripts.net/pP3x3T

Then in your admin panel, click "Regenerate Assets" from the cog icon.