This game is in dire need of a fix. Every 45 seconds the game shuts down and displays a "WebGL context lost. You will need to reload the page" error
Go to Settings → System → "Use graphics acceleration when available" and make sure it's turned on.
After enabling it, restart the browser and reload the page. This usually fixes the "WebGL context lost" error, especially if it's related to disabled hardware acceleration or GPU rendering issues.