Echoes of Saltmarsh in overall tone. The Scarecrows are great, I'd have liked an "order of battle" for them, I imagine if conflict is started with the farmers the Scarecrows show up to cut off escape routes for the players forcing them to fight through them or take to the sea.
A solid entry with emphasis on a chaotic chase/rescue. An unspoken piece of design I noticed was that rummaging through the generous treasure closet also is a race against time, you might have to split your attention between rescue and loot. Something that could have made this challenge even starker would have been marking the treasure closet clearly for the players but locking it so that it takes time to get any at all + lockpicking vs. destroying the door. Right now the prisoners are encountered first and the treasure might be missed completely. I'd have put the prisoners and treasure in the same room!
I like the old-style diving suits in Guimond's Light. I have a little area in my Dungeons & Drains tunnels below a palace that has an air-lock. I think I'm going to steal the notion of having an old diving suit there that's sort of decaying with dry-rot and mix that with Prince's contest to use standard AD&D spells in innovative way -- i.e. the suit was originally constructed from materials and craftsmanship that exceeds the local tech...so it can't be repaired excepted magically via a mending spell or better.