Sure, I'm happy to offer some thoughts. I want to caveat that I didn't spend as much time preparing for the adventure as I would have liked, so I might have thoughts about the game that are actually covered in the booklet. Here are some questions and some comments on how I ran the adventure.
1. The hatch leading from the staircase to the Lantern Room. Which way does the hatch door open? Does it open into the Lantern Room or into the Stairwell? I ran the adventure with the hatch swinging down into the staircase.
2. Does the key (from the loft bed-side desk ) open the padlock that leads to the Lantern Room? I allowed the key to open the padlock. A player asked if the the padlock on the hatch meant that the person in the Lantern Room was trapped. I told the player "yes" and later in the adventure argued that Macneil ordered O'Connell to lock Macneil in the Lantern Room. Maybe add another sentence to explain the padlock on the hatch to the Lantern Room.
3. How big are the windows to the cottage and store room? Can a person climb through one? I did not allow the windows to be big enough to crawl through but could be seen through.
4. Is there an intent around the fog horn inoperable? Can it be repaired or can grease from the storeroom be used to "un-seize" it. A player thought to use the grease from the storage room to "un seize" the fog horn. I liked the idea and let them do it. But that player had to keep cranking the fog horn to keep the fog horn working. I allowed it to "warn" the approaching ship.
5. The signal flare (wrapped in oil cloth) could use some more mechanics and intent. Is it a torch or is it bright enough for the approaching ship to see? What level of technology is the signal flare so that it is consistent with the rest of the adventure? Is this a place for a magic item? My players did not explore the fishing vessel and I don't know what I would have done for signal flare mechanics.
6. Is the ochre paint flammable? If so, what might that do for game mechanics?
7. Alistair Macneil. What weapon(s) does he have? I recommend reconsidering Macneil's number of attacks (listed as 2). I think players familiar with Knave could cry "foul" at an NPC human getting two attacks. An updates to the "Knave style" for this adventure might benefit from including Armor Pieces to justify the Macneil's AC 14. That is three (3) Armor Points or pieces of armor. For example, maybe Macneil is wearing a gambeson, chain shirt, and helmet. But how did a lighthouse keeper get armor pieces? With my players, I dropped Macneil's attacks to one per round. I kept the AC but in retrospect, I wish I had lowered it to AC 11.
8. If I ran (hopefully WHEN I run) this adventure again, I would emphasize upfront to the players that after a general exploration of a new area or room, that they need to declare they are "searching" an area or room and that such a detailed search will take 10 minutes (1 turn). Given the brilliant mechanic of the ticking clock and tables for events each turn, this will create "important choices" for the players on how they want to spend their time. I would emphasize this search mechanic, because I didn't know how to give my players a better chance of finding the several secret doors that available in the adventure (all of which are excellent).
9. Adding some mechanics (like a DEX or STR check; or fall damage) about what happens with four-story staircase room. My players figured out the danger of the stairs (2 PCs climb the stairs at once, they break). The signposting of danger was good. But, another sentence around what happens to the players and what they might do to mitigate damage or impact from the stairs break - would be nice.
10. Another "when I run this again", I will explain to the players (during the adventure intro) how the lighthouse works and what it does. That is, there are three main components (wick, oil, lens) and that the light from the house provides a reference point for ships to steer clear of danger. This may seem obvious, but I think it might ensure clarity for the players who may not be nautically savvy.
11. Malcolm Fraiser. I recommend adding some more information about the iron shackles holding him in place. Is there a key for the shackles? If so, where is the key (likely with Dylan O'Connell, if I had to guess) ? I recommend
Hopefully some of that is useful.
I loved this adventure. Well done!