Realistically, I would've stopped the moment BASIC worked, called it "good enough," and then gotten distracted attempting to write a Forth for it.
So while the video is impressive and I couldn't do something like this myself, I was glad when I saw how bad it ran, as that computer of mine would a little bit more than 30yo today, so to have that beat by a 40yo printer controller would make me think I could have done something to have it run better back then!
I mean, sure, major props for kludging your own video generator in there, but...