I didn't like this book all that much. I feel like it was a lot of build up only for it to end in a crestfallen flump. Very dated too, but for a book with its publishing date, you should expect dated language, so I don't dislike it for that reason alone.
Call me stupid if you want, but I didn't really understand if the ending was literal, figurative, or 'it was all a dream' kind of thing, and my search online for answers haven't held much fruit despite how old (and apparently obscure) this book is. I've heard from other reviews here that I should give it another read through, and maybe I would understand it then, I admit - I do love other media with similar strategies to fully appreciate its ending, such as Triangle or The Matrix off the top of my head. You miss hints and clues the first time round and it makes you want to watch it again armed now with the knowledge you have to see if you can spot a deeper meaning, and solve the puzzle of the mysteries.
This though I feel isn't the kind of book I'd want to read again, knowing that it ends the way it does. It feels like you're just getting your teeth into it, having a deeper understanding of the cast of characters, that its trying to tell you something, and then its over, like an episode of Alfred Hitchcock Presents.
Its not bad, but not especially good, either; At least in my humble opinion. I can see three possible meanings to the ending, and I can't decide which one I'm most happy to settle on.
If you're looking for other 'groups lost in the wild and have to survive a threat' type of story, there are a some other ones I'd recommend. A few I could name off the bat would be The Pact by Sharon J Bolton , The Last Restort by Susi Holiday, The Troop by Nick Cutter, Hide by Kirsten White or Predators by Michaelbrent Collins