Hi, I installed a new browser on Linux (Brave browser, which is a Chromium based browser). At first it seemed to be doing the same problem where the <enter> key would not work, but similar to how you described after a few tries the <enter> key did register and I was able to proceed with the game's execution, thanks. Still not sure why I had trouble with Firefox running under Linux, but in any case it seems to work with the Brave browser. I also tried to click on the screen with the mouse cursor as you suggested to ensure that the App had the focus, but I think I did the same with Firefox also. Thanks for your help!