Basically it's an entire 90 kilobyte program that draws the animation! Edit: 90 Megabyte!
Something like this could have been possible back in the day, given a DMA capable i/o transfer device.
LDA #PIXELS
STA #SCREEN
. . .
The result is pretty great. I will enjoy the details.
Still, while technically possible to do this sort of video compression in 1981, it would have involved extremely specialized hardware to scan the film in the first place, and a good amount of compute time on a real big machine like the Cray-1 to do the compression. (And Rick Astley wasn't a star yet, so what would have been the point?)
Fun fact though: just two years later, Cyndi Lauper's iconic music video was edited in digital form, including the insertion of computer-processed video effects: https://youtu.be/PIb6AZdTr-A?t=90 While such things as picture-in-picture are so common today we don't even notice it unless pointed out, that was mind-blowing at the time. But it took hardware worth a million dollars due to the megabytes of RAM required to fit the 10 second clips they worked with.
Mechner pioneered doing that from VHS when doing his game Prince of Persia.
Something like Bad Apple would be a heavy lift.