Okay, let's add roads and ground-based cars driving on them below the buildings, while keeping the river and reflections.

Now you should see a road layer below the buildings with ground-based cars moving horizontally in lanes. The river is below the road, and reflections of buildings and flying cars appear in the water.

Okay, let's add a moon to the sunset sky.

A pale moon with a subtle glow should now be visible in the upper right portion of the sky.

Okay, let's shift the scene to nighttime. This primarily involves changing the color palettes for the sky, road, and water, making the lights from the moon, windows, and cars stand out more.

The scene is now set at night. The sky is dark with twinkling stars, the moon glows brighter, buildings and cars are darker but their lights (windows, headlights, taillights, trails) are more prominent with added glow effects. The road and water are also darker to match the nighttime ambiance.

Okay, let's increase the density of the buildings significantly. We'll achieve this by making buildings generally narrower and reducing the gaps between them in the main.js file.

The cityscape should now appear much denser, with significantly more buildings packed closer together. I've adjusted the building generation logic in main.js to use narrower widths and smaller (even negative, allowing overlap) gaps. I also slightly simplified the ripple effect in building.js to potentially help with performance, as drawing many reflections can be demanding.