I've only watched gameplay of Terra Nil, but it seems like it's just an environmentalism themed puzzle game. You could replace all the titles with colors, and all the buildings and what they do with arbitrary rules, and it seems like it wouldn't look anything like an ecosystem sim. It would be like taking the game Lights Out, changing dark spots to "growth", light spots to "wastelands" and saying the goal is to balance out the ecosystem.

I didn't see the late game though, so maybe I didn't see where it shines.