As we indicated in our earlier Dev Goals post (below), one thing we're working on is our final transition into full-color character sprites with shading and color swapping.
https://store.steampowered.com/news/app/1492750/view/3888359911119183911?l=english
The first character to get this upgrade will be Paul. We are making steady progress on his art and hope for full-color Paul to be playable in-game later this month. The next will be Billy, then either Noel, Lewis or Nick. The last to get upgraded will be Marv since his animations are the most complex.
In our finished sprites we will actually use two layered images per frame of animation. One has only lineart and shadows with a standard sprite shader (written for us by TooMuchAbstraction, the developer of Waves of Steel--check his game out when you get a chance!), then a second sprite contains only flat shades of gray which is run through the swap shader.
Before rendering a sprite set up for color swapping, this shader reads the intensity (lightness/darkness) of its pixels. Each shade of gray maps to different color within a palette texture, and the shader assigns that color. Then to change character color palettes we just switch palette textures. Each of those is just an 8x1 pixel image, so they're easy to make and, in theory, anyone could do it.
Thanks for your continued support. Hand drawn art is very labor intensive and time consuming, but we're really excited to be entering this stage of development.