Thanks to Opus/5.2/3Pro (I used all in various capacities) I was able to make a version of Mini Metro with some of my own quirks. I wanted residential/office space densities, so station placement is strategic. I also wanted a real economic engine like Transport Fever/City Skylines type games, so it costs actual money to build stations/lines and keep operating them, and you make revenue from metro tickets.

Feel free to suggest ideas to add to increase the game dynamics and complexity, I am all ears! This is the first time I have tried my hand at making a game. It is open source and you see the source code on https://github.com/championswimmer/metromap.io