Due to time and cost constraints, Sickness launched with several backgrounds that don't match the others.
Now that Sickness has been released, these backgrounds will be phased out one by one over the next couple of months and replaced by new backgrounds to provide a more consistent experience in terms of style.
Once all of the inconsistent backgrounds have been replaced, work on new routes will begin, including more "good ends", choices involving who to spare/kill, and a couple of new characters.