A longer review is posted here: http://theotherside.timsbrannan.com/
This is a meaty module. 84 pages, covers, maps and OGL still leave a lot of pages for material.
First off, if you are not familiar with Dungeon Crawl Classics modules they are meant to emulate a certain feel of early 80s play. They went on to create the game Dungeon Crawl Classics, but the adventures are still largely OSR compatible. Actually I didn't see a single thing in this adventure screamed is should be used for one system or the other.
This adventure is actually 3 adventures in one. Legacy of the Savage Kings, The Lost Passage of the Drow, and War of the Witch Queen. Each one is a different part of the Witch Queen's plan.
Reading through this adventure is one part excitement for the new and one part excitement for the nostalgia. For the new, I wanted to learn more about Kyleth (the eponymous Witch Queen) and the tome Ars Maleficus. The nostalgia comes from many little easter eggs through out the pages that call back to adventures of the TSR-days. I am convinced the Mad Hermit here is the same as the one in the Keep on the Borderland for example. There are also hints of influences from Vault of the Drow, Ravenloft, and even the rest of the GDQ series. In fact the second adventure, "The Lost Passage of the Drow" could be slotted into the D series and no one would be the wiser. Replace Baba Yazoth with the proper Baba Yaga and have one of the many adventures she features in as a side trek.
There are a number of named characters that would work well as witches, Maeve, Baba Yazoth and of course Kyleth herself. While using the title of "Witch Queen" Kyleth is only an 8th level Magic-user. Make her a 9th or 10th level witch and then you have something really scary.
Does it work with The Witch? Yes, absolutely. There are number of great items and story points in this adventure for any witch character. In fact I would say that any good witch would want to see Kyleth taken out on general principle. Plus there are a number of encounters and NPCs that would benefit from the rules in the Witch. Night Hags get more spell casting powers for example and the medusa can also have some levels of witch.
Of course there is the one issue of Kyleth being one of The Thirteen. The Thirteen most evil wizards, witches and necromancers in the world. She was the newest member, who are the other 12 and what are their plans? Anyone up for an adventure against the Legion of Doom? I might have to come back to this idea. I can see witches, vivamancers, blood mages, evil wizards, and necromancers part of this evil cabal. Each providing something different.
Seriously, there is so much fun stuff here I can't wait to try it out.
[5 of 5 Stars!]