First off, I love the art and typography. The document's monster layout and design in general is professional and solid. The background is a solid pitch. I also really like that you could just drop the island on your map and head over to it from a hexcrawl. The bounty board, bullet-point features of locations... I'm stealing that for my next adventure, or at least going to try and do something similar.
The effects of freeing the spirits are really cool... And their designs.
I'm honestly kind of bad at criticism, I don't see anything negative about this adventure. Absolutely love it. Well-done, and inspiration for how I can make a better one. Beautiful art.