The secret behind all this is procedural content generation. in a nutshell, instead of storing a movie as-is we're storing a certain number of mathematical formulas for image and audio manipulation as well as the "recipe" how to apply those small bits of code in a way that what you see comes out. And while it's running your computer's graphics card cares for the actual displaying ot the world, just like in modern 3D games. Formulas+recipe are of course way smaller than the end result, and with a few additional sprinkles of magic compression fairy dust we get down to under 200 kilobytes, which is way less than one single high quality image of this show would take.
This of course means, no, we don't have any magic technology that can compress videos down to that size, but the video has to be authored in the way described above. Manually. With, like, lots of work involved. Making this gem took us all more than two years of hobby part time work _after_ we had five years of experience with this kind of technology.