itch.io

We see that in this case they use a separated color palette for the background so this will be solved with a very simple script tagged "layer_adjust"

function UpdateS()
    if shape2D.Palette == a then
        shape.Layer = 2; -- layer 2
    else
        shape.Layer = 1; -- layer 1
    end
end

then tag all patterns that appears in multi layers with the same tag, try a value for a that works (from 0 to 3), there are just 4 palette for background

Or if that's true for the whole game so we can use this script with tag "*" without quote for the whole game

function UpdateS()    
    if shape.Bg and shape2D.Palette == a then      
        shape.Layer = 2; -- layer 2
    else  
        shape.Layer = 1; -- layer 1
    end
end