I don't have any plan to add new scenarios in the foreseeable future. It is not easy to create a new one, and there are a lot of other things that have come up in life in the 10 years since I started this website. However, in that time others have started to build scenarios and have ported a version of this game to a new site. Instructions on how to play the additional scenarios are here.
I have noticed this myself, no timeline on fixing this, unfortunately.