The issue can be fixed by Chrome users without changing browsers, but it's a fairly complex issue which involves: 1) possibly installing a plugin, 2) disabling a different plugin, 3) possible additional steps to REALLY disable that plugin, because for some users Chrome automatically re-enables it after the normal disable method, 4) clearing the Flash cache, 5) re-setting Flash's Global and Local (for this site) Storage Settings.
How do I know all this? Because I did the Google research myself, and had to perform ALL of the above steps, each of which in itself consists of many steps. However, I am finally rewarded with a Chrome browser which plays WGT, and the spacebar and everything else is working.