I adore the atmosphere that each of the generated cities have, especially with how the background elements can compliment/contrast with the city in front of it. The background variant filled with spikes is my personal favorite; feels reminiscent of old nuclear warning concepts which is perfect for a sci-fi setting!
Bruh, the nuclear waste warnings concept is the precise inspiration for this background ! Glad to see somone know that crazy stuff.
The red biome is the hot/volcano biome, so I tought it would be a great idea to put this particular shape here, both disturbing and forbidding, perfect for an hypothetical Alien landscape.