It's looking good. My only crit would be that the human characters seem to disappear into the BG, because everything in the foreground is coloured in the same way as the BG. U could even go slightly deeper with the hues in the foreground so the central characters stand out more. And also remember that generally everything that is furthest away in the BG (i.e the Horizon) is paler than the foreground. This creates depth.