Not only you can dance along with the demo, we also encourage you to peek at A Saturday Night source code on Github. The most interesting part is that it shows how to track the user’s movement and position (both headset and controllers). And, you can easily reuse that code in your own A-Frame projects too!
The tracking code has been released as a standalone A-Frame component, which you can grab from this Github repository or via NPM:
npm install aframe-motion-capture
There are a few controllers in that repository. The highest-level controllers,
avatar-replayer, allow you to record and replay the avatar’s movement (head and hands). This is very useful for QA or automated tests –where recording and replaying what a user has done has tremendous value. There’s also the possibility of exploring new use cases: game mechanics or other types of interactive activity that could benefit such as controlling character movement, casting spells by gesturing with your hands, etc.
Source: Mozilla Hacks A Saturday Night: Track and record movement in WebVR