I would be plain - this is a single example of the most dark, gloomy, ambient, oppressive and hopecrushing novel i have read in years! And it is - AWESOME!
To be fair - it should have 2 review scores, because it's score actually depends on people who read other Tallarn stuff before, and people who hasn't, and read only 1 page fluff summary. For the second group Tallarn is '10 millions tanks' - biggest armored clash in all HH (probably till the Siege of Terra). This group should not touch this novella - they would be pretty disappointed. Not by the writing style (you can't unlove this kind of writing), BUT - SPOILERS, BEWARE
it's not in the book ;) (Ok it is - in several sentences of the narrative)
But for the first group - this novel-novella (decide how to call it yourself) IS BEYOND GODLIKE. As i mentioned in a previous Tallarn review - John French is a true master of ambience, occultism and fear. To give him the praise, he actually deserve - i would call him a true Lovecraft for Black Library.
Anyway - people who wants to know the dark stuff, the secret plotlines and the actual story behind all that Tallarn conflict, - should read it! You will not regret your time. It's money and time well spent.
PS. People who wants a 10 mils of tanks battle for 230 pages - do not read this book, wait for the Forgeworld Tallarn HH fluff book. They will give you 10 mils of tanks ;)