Bleak Isle is a violent and nihilistic horror adventure for FIST. For real, the content warning isn't messing around. There's a lot of description of human meanness and gore in here.
Visuals-wise, the PDF is 12 pages with a gorgeous, emotive cover and a really nice, atmospheric full page interior illustration midway through. The rest of the PDF is more straightforward, with clean, easy to read text but no major flourishes.
Contents-wise, the tone here is more gnarly and somber than almost any other FIST material, but it fits in perfectly with any other tense modern slasher.
The writing is strong, and the setup (a bunch of slashers lure the FIST team to an island to hunt them) makes for a solid premise. There's a lot of individual encounters that have some interesting texture to them, and the GM has a lot of freedom to scale the threat level of the scenario based on how the players are doing.
Mechanics-wise, each foe is a unique challenge, and combinations of foes can shape some extremely interesting tactical encounters. However, the hook for getting the PCs to the island isn't actually baited, and to some extent you're relying on the players choosing to stay to play the adventure, or else you're having to actively work as the GM to cut off their routes of egress.
Overall, if you like your game of FIST heroic-toned and A-Team-y, don't use this. It's very much a subversion of that style. On the other hand, if you like scenarios for Delta Green and movies like Don't Breathe and Wrong Turn where there's a genuine nasty edge, this fits that style perfectly. And if you want to repurpose this scenario for something like Hunter or Delta Green, I think it would work very well in that regard.
-A map would add a lot to this scenario. It's possible to figure out where everything is just from the book, but it's a little slower than using a map, and this scenario wants to feel very immediate.
-This is such a weird quibble, but the Sixteen feel a little more like renegade FIST members than renegade CYCLOPS ones. CYCLOPS and FIST get along so poorly in core that it feels strange CYCLOPS agents would nurse that kind of grudge against their enemies, whereas abandoned FIST agents could *definitely* get this weird and violent without it feeling out of character.