In format, it's a copiously and sometimes inaccurately illustrated forty two page PDF. The first ten pages are illustrations and backstory. As most of it is irrelevant to the players or the plot, I used it for inspiration and freely changed details to make it fit in with my campaign.
Despite the fact that it has a whole city to play in there are only three set encounters outside of the building where the MacGuffin is held. The city is divided into four parts:
The western bank of the river Wolfen, which is held by the defenders;
'No-Man's Land' - those parts of the eastern bank visible to the defenders where the party can be attacked by BOTH sides.
'Altered States' - those parts of the city devastated by the magical attack that leveled the city walls
'Utter Mayhem' - everywhere else in the city.

Each type of the area on the east bank has a short list of random encounters, with a 60% chance pf encounter every ten minutes. I thought that would be far too small of a selection, but in play it turned out that no random encounter was ever repeated.
The action is divided into two scenes to use the Mythic terminology: getting to the City Hall and finding the MacGuffin inside the building. There's a climactic fight on the roof before the party exits via a balloon.
The motivations for the two main NPC's are what makes this module so much fun to run. The adventure starts off with the party trapped in the doomed city and drafted into it's last desperate defense against the horde of mutant Chaos worshipping barbarians. Their sergeant volunteers them to assist a nun in recovering a Holy Relic from the other side of the river. Except she's not a real nun she's a cat burglar who's been truing to steal the relic and sees her chance in current situation. And the sergeant is actually her accomplice. So the party is being used as dupes and meatshields to begin with.
Even better as the horde gathers outside the City Hall, effectively trapping the party, the cat burglar/nun leads the way to the roof where her accomplices are waiting in a balloon to lift the party to safety.
Except the accomplices have decided to double-cross her.
Play report below the jump.