I'm not sure what would cause this, something is causing it to fail to sync the virtual file system, but I'm not sure what would do that. Possibly some sandboxing problem? You could try clearing offline site data and see if that helps.
Oh, I think that's it. I tried running it in an Incognito tab and was able to reproduce the problem. It doesn't currently support running with local storage disabled.
I'll try investigating this over the weekend, but you should be able to play it if you run in a regular tab.
