Looks like it's working in Internet Explorer, but not in Firefox (latest version).
Can't get a HTML5 Unity game (built in Unity 5) working either, but that's a different problem caused by Unity 5 being ornery in general about its Web player replacement. At least partly so; Itch.io is telling me that even my super-basic game build has no index.html in its ZIP file, even though it definitely has one.