then u might want to read up about "pure object oriented" programming languages, which this is made from. basically everything in the video is an object that can be modified/updated dynamically (theres no compiling), this could means while you play your mmorpg you can look at forum boards inside the world and make your character post a replay, or create a new world and jump inside of it on the fly,..stuff like that. and theres always drawing your game and then playing at the same time. check this video