Since the games themselves are written in Java, could you potentially make another implementation of Flax that runs directly on JVMs (e.g., directly on Android without using the browser)? Or it it tied to closely to GWT to do that reasonably?
Potentially, we could do so, yes. It would take some time, though, because the engine is centred heavily on creating map object from a JSON string, which probably wouldn't work so nicely out of the box in a simple JVM (though to be honest I haven't looked into it).
I just brought that up because I found that to be a drawback of ImpactJS[1] when I tried out some of the demos—they didn't run well on Android. By allowing the user to compile into both JavaScript and JVM versions, you could avoid that issue.