FPS Engine based off of the PlayfulJS FPS JS Engine.
This engine is implemented in Java rather than JS. Furthermore, the engine extends the basic tutorial. Pushing the engine code into its own class, and placing game specific functions in their own class.
As of 9/13/14, more of that transition still needs to be done. A lot of the top level raycasting designed by Hunter is still in its own class while looping is down in a proper engine class.