It could be nicer if it reverse engineered the speckles of different densities from the error diffusion dithering back into nice smooth continuous gradients.
As it is, it just leaves a bunch of individual dots in, but those could be detected and their color spread out to make a gradient. Like near the horizon of the planet, and the skulls and bones, for example.
Of course you'd need to detect and mask out the area that the gradient applies to, since you don't want i.e. the color bleeding out past the edge of the planet into space, or into the outlines.
As it is, it just leaves a bunch of individual dots in, but those could be detected and their color spread out to make a gradient. Like near the horizon of the planet, and the skulls and bones, for example.
Of course you'd need to detect and mask out the area that the gradient applies to, since you don't want i.e. the color bleeding out past the edge of the planet into space, or into the outlines.