That’s a sweet spot—retro vibes for nostalgia, but with green tech for future. Start by sketching the city’s skeleton in pixel art, then layer in holographic streetlights that harvest ambient light. Use modular, prefabs that can evolve, like living code blocks, so the grid can rewire itself if the sun drops out. Keep the UI minimal, like old CRT menus but with adaptive brightness. And don’t forget a “heartbeat” loop—random bursts of neon that sync to local foot traffic, so it feels alive. Trust me, the real twist is letting the city learn from its own glitches and remix them into art.