OMG that is a crazy score! Yeah it's an interesting question, a simple solution would be to reduce the number of extra tiles you gain when creating a perfect tile, but it might seriously limit the size an island can become. Maybe reducing the perfect tile reward and implementing another means of gaining additional tiles such as completing quests like connecting X number of desert triangles or X number of forest triangles could be a nice solution as it can become harder to complete the quests the longer you play. I'll think some more about it and maybe add a little update after the rating period :)) Thanks for playing!