2.1.9 Game Skeleton Hot!
Each state has onEnter() , onUpdate() , onExit() , and onRender() methods. The skeleton provides a stack-based state manager so you can push a pause menu over the running game without destroying the running state's data.
I once consulted on a project that was "90% done." The developers had built a beautiful open world. The textures were 4K. The orchestral score was stunning. 2.1.9 Game Skeleton