Fun game, but I was either very unlucky or I uncovered a bug. I picked up the 4th castle piece before finding the 3rd in my deck, and in the end I never got the 4th piece. (population 356, pulled at least 150 cards after placing the 3rd castle piece). I finally lost by filling my hand with quarries when the island didn’t have any stone, which was a bit of a disappointing end.
Regardless, really good work!