It would be fun to see a set of frames rendered out and stitched together to make an animated sequence. 17 hours per frame. It'll be like Pixar where you'd need a render farm of Speccy's to knock it out.
One could "cheat" by running this in an emulator of a massively overclocked ZX Spectrum to cut down on the render time and still get an authentic end result.
Also, not exactly the same type or rendering, but basically word for word what you wrote: the full-screen fully animated parts appear to be "a set of frames rendered out and stitched together to make an animated sequence"
Amiga is famous for The Juggler, an animation by Eric Graham which did exactly that in January 1986. It became an Amiga "mascot" of sorts and the animation was used to advertise the machine in computer shops, magazines, etc.
I did some extremely rudimentary animations on my Spectrum 128 in Beta BASIC this way.
I generated a couple of dozen frames of a Julia set distorting, in monochrome, saved them to the RAMdisk... which took a couple of hours or something... and then loaded them back in sequence from the RAMdisk, which gave me a few frames-per-second "video".
It worked and it fit into 20kB or less of code, and about 90kB of RAMdisk.
