How is the interface of this site built ? What's going on here ? Any hints would be appreciated. Thanks.
I am sorry for answering instead of commenting but I lack the reputation. I don't think I understand your question. What exactly you want to know?
As far I can see the website was build by front-end developer(s). It uses Node.js, socket.io, three.js for 3d rendering, TweenMax for the animation and navigation. Sites like this can be designed with tools like Just In Mind or most likely for this website, they used a video animation tool, like CINEMA 4D.
I hope I helped answer some of your questions