It's all scripting. Last time I looked at povray modellers for Linux, admittedly 20 years ago, I didn't get on with any of them. Last modeller I used was Moray for MS-DOS, but that's limited to a pretty old version of povray, and raytracing under DOSBox would slow everything down. But scripting allows me to use macros and procedural generation. So all those streets of buildings are generated from the same macro with random variations, and the trees and bushes also come from the same macro.
That's a cool video! I just realised "those streets of buildings" I mentioned aren't actually there in that unfinished render. You can see them in this completed manual cover image (a further progress pic just to stay on topic...) with a handful of actual game screenshots alongside. The title screen was hand-traced as you need a lot of artistic licence reducing this level of detail down to a 144x144 pixel image. 