Every color can be described by four properties. Knowing them makes it much easier to fix a picture that "looks wrong". Each of our six worlds uses them differently.
Hue. Hue is the basic color name: red, blue, yellow and so on. Colors opposite each other on the color wheel, like orange and violet, make each other look stronger. Neighboring colors, like several blues, feel calm together. Ocean World uses mostly violets and blues, so it feels calm.
Value. Value is how light or dark a color is. It matters more than hue for readability. If a picture looks muddy, the values are usually too close together. Our worlds read clearly even in grayscale: bright sky, darker hills, darkest ground.
Saturation. Saturation is how intense a color is. Most of a scene should be muted so a few saturated colors can stand out. In Forest World, the glowing mushroom caps are the only saturated colors against a dark teal night.
Temperature. Warm colors (reds, oranges) seem to come forward. Cool colors (blues, greens) seem to sit back. Volcano World is almost all warm and feels close. Frost World is cool, so the green aurora immediately grabs attention.
Try it: take a screenshot of a world and turn it grayscale. If you can still tell what everything is, the values are working.