Thank you for your kind words! I realize some puzzles are far from casual to reason about, but if you tink it trough (especially island 3 is a tough one) using only logic and deduction, you will find there is only one solution possible. I was thinking about adding the explanation to each puzzle as well, but thought that would become a bit tedious and only 1 or 2 people would be actually interested in it :). that said. if you have your doubts about a specific puzzle, I would happily share the reasoning with you.