How to get the color/contrast right for a game with space backgrounds?

I'm working on a 2d platform shooter, set in space. I want it to thematically be as spacey, alien, sci-fi as possible. However, I don't want it to be SO in space that there is no terrain environment, because the player needs to be running around on stuff, exploring caves and so on. This might be taking place on an asteroid or small moon or space station for example.

For backgrounds I'd like something along the lines of those seen in Steredenn. Colorful space scenes of things like nebula, planets, asteroids, etc. Except that, in Steredenn the backgrounds can be very saturated and bright. So much so that all enemy ships are black and gray/desaturated and dark to try to strike a contrast. There's even one level with a bright yellow sun taking up most of the view. It works because there is no foreground terrain at all and most objects are either very dark or very bright/colorful. e.g.



In my case, I want a detailed terrain to interact with. Thinking along the lines of e.g. BroForce. In fact most 2D platformer type games. I've noticed that MOST of them focus on a reasonably DARK landscape, where the SKY is quite bright. This is because they're set on planets with atmosphere. They may feature multiple parallax layers which look nice, fading into a lighter sky. But they don't look AS "spacey", and any space objects would have to be very light silhouettes in the sky - hard to see in "daytime". In fact the idea of using "fades to black" space backgrounds kinds of suggests a NIGHT-TIME theme, which seems confusing if the terrain is more lit? Usually the atmosphere blots out any space backgrounds e.g.


Obviously contrast of brightness, and contrast of saturation is quite important. If the foreground goes "dark", then the background becomes the source of color and light. But this also tends to bring the background forward. And having a really dark main terrain to me is "hard to read" and unintuitive, it's kind of not what our eyes are used to trying to pick out objects in the negative. And then the terrain being so dark to contrast against the sky, makes the terrain itself less aesthetically pleasing. e.g.


Another example being Dead Cells... which overall looks nice, darker foreground, some detail in the terrain, most of the color is in the background (e.g. if it were nebula and such). But it does push the foreground to go dark. There has to be sufficient contrast for easy edge detection for platfroming.



I thought about maybe going with a lighter terrain and then push the sky to be darker, restricting the colorfulness etc of the backgrounds. e.g a very rough mockup...



Having the terrain be mid-level brightness with more saturation seems to make sense, though it forces the background to have to be darker in order to produce contrast to distinguish them. Also I want to have at least 1 layer of parrallax, and somehow that has to work as well. The only way I could seem to make it look reasonable is for the parallax to be quite dark as well.

Is this my only option? A brighter foreground with a darker space background? Are there any alternatives which might allow the space backgrounds to be brighter while still having decent color in the terrain? I want the terrains to have a variety of colors across levels as well so they can't just be gray/black or highly desaturated.

It seems its either:
A) very dark terrain with mid-level backgrounds
B) mid-level terrain with darker backgrounds
C) extremely bright terrain with mid-level backgrounds
D) dark-mid terrain with a very bright outline, separating it from colorful background?
?

 

A basic mockup with a bright terrain outline... ?

It sort of seems to work given some of the background is dark and is a bit less saturated, versus the bright saturated edging? The background image here I enhanced contrast to make sure there are some dark areas as well as bright. Is there enough contrast in the bright areas to distinguish it from the terrain? Should I avoid having backgrounds be too bright, to avoid clashing with moving objects etc?



And with a parallax layer - less saturated, darker ... guarantees more likely contrast?



Here I added edge lighting which also increases the contrast, I guess it helps? Seems to make it look less 'floaty' and more depth?

 

I'd think about contrast and value in relationship to player focus.

Mostly we should be focused on the player, the enemies, and maybe some special items. The background is important but use contrast and value to make sure it stays background - doesn't compete for attention.

Beware evaluating art in isolation from the rest of the whole.

 

Turn you game into grayscale. You can use filter. And you will recognise immediately, where color choices are wrong.