RetroGaming

There's a sweet homebrew city builder for Game Boy Color / Game Boy advance. It gives vibes like SimCity for SNES. It's also totally free AND works on real hardware.

GBA: https://skylyrac.itch.io/ucity-advance GBC: https://github.com/AntonioND/ucity/

I'm not affiliated with the project -- just a satisfied player. If you like classic city building games at all, this deserves a try from you.

Have fun!