The setting is well written, nicely laid out for the GM, and packed full of hooks, NPCs and encouters. The premise is fascinating and very original. It's a castaway sandbox mystery where the players unravel a terrible tragedy. The factions are great. The Spiritweaving magic system, involving bargaining, is really cool and would make a great addition to any game heavy in the supernatural - it would makes sense in Blades in the Dark - if you could work out the mechanics.
I'm a sucker for nautical adventures, which is why I backed it. Unfortunately, I can't ever see running it. The settings doesn't fit with games that I'm interested in running. The good news is there is a lot in there I could see cherry-picking for other games - the spiritweaving, as I already mentioned, a decent amount of stuff that could be repurposed for a nautical adventure, and some great, pre-made NPCs.
It's more complete setting than Lost Lighthouse (another recent KS delivery starting with ending up stranded on an island), but it's also a full book and not a zine. And I think I'd run LI in something. This, I just don't think so.