The past months we have been working away on production-level art and during that process have tried to figure out different aspects of our workflow and rules to help the art compliment, not get in the way, of game-play. The first area where we felt happy with the level design is the inverted gravity backworld, so we decided to start there.
The settings for this particular world are inspired by airships and renaissance design in the frontworld and sci-fi space stations in the backworld. We have tried to make each room distinct in some way and in this case it was a fairly easy choice to simply do that by giving them a functional purpose in the airship/station.
We also tried to map these areas to each other as much as possible between frontworld and backworld. In the screenshots you can see that a library is mapped to a server room and a cargo area is common between both. Similarly we also mapped objects between them, for example the foreground clouds are all satellites in the backworld. The reason for mapping them is to create another connection between the worlds which helps when drawing since it makes the differences in structures that are important to gameplay easier to identify.
Other than that we had to work a lot on the colors in general. For the background sky we had many iterations to figure out what would not be distracting while also interesting when giving attention to it. For the backworld, coloring mostly comes down to having contrast between what is solid and is only background and making sure you are not confused about which world you have drawn to at a any given area.
We will probably do a first pass on art for all our worlds before we continue to add animation, particle effects and some more detail work to all of them. We have started the first pass on one other area and will get started on yet another soon.