Create 2D games in Lua and LÖVE.
love2d.org
love2d.org
It allows you to write (multiplayer) games that execute in the Browser. Lua is executed on the server side. The browser side is implemented in GWT and is getting pushed the game state.
One recommendation: https://github.com/kikito
That and there's no consistency between libraries as far as how they decide to use classes.
This problem actually became so severe that there is now a "common interface" that libraries can use on each other's objects.