Alright, First off, Love this Book. It's well put together, well thought out, pretty complete, and overall a Darn good Story.
Here's what I intend to change.
Even though the book provides some alternatives to starting out the game so you can incorporate the intro scene into your campaign, i found them kind of lacking. Since my campaign starts with Broken Chains, which has them crash land into False Prophets, and then we lead into the book from that storyline leading the characters on the path to Rivals for Glory. I then used Rivals for Glory to get them set on Hand of Corruption. I pretty much skip all the gambling part and let the idea of Stealing a Planet be both a treasure they are presented with and a passage from the False Prophets book ("Together they have the strenth to move planets"). A lot of the intro from Hand of Corruption seems very railroaded, but in my version, it gives more of the We-found-it feel then the it-was-handed-to-us feel.
The Next problem has already been discussed in these forums. How to get a CSM to infiltrate a prison.
My players and I have a couple of good options. Lots of people seem very distraught at the idea of having a CSM give up some of his best advantages (armour and weapons). If your players think they can manage without that stuff great. If they managed to get there hands on the Slave Girl, then they know that outside the one city there is nothing but barren waste land. So, you the sorcerers of Q'Sal(getting a favor from them was an entirely different story) to outfit a Missile or Drop Pod with some special Chaos powers to it goes Really Fast, and since normal humans wouldn't survive a drop pod anyway, they launch their armor into the middle of nowhere and go retreive later and hide in the tunnels until it times to spring their trap. No one would think twice about sending a hulking mutant to prison using the other ideas presented in the book and he still gets his armor and weapons for the big fight. Another idea was he uses some infamy and goods to have some trusted follower find a way to drop it off in the middle of nowhere or deliver to the catacombs and hide it with some kind of homing beacon on it.
Another way, if the players have made contacts with the Dark Eldar, perhaps they can find a way through the webway to get there. Perhaps having to perform some deed or trade slaves to earn passage behind the Imperial Ships and planetfall into the wasteland and infiltrate from the ground.
The other major problem I hade with this adventure is the lack of options for Failure. Lots of skill tests are mentioned. And I mean lots. But almost no consequences for failing. Falling on some of my old Dungeon Magazine experience, and from the podcast Nerdbound, I added some twists. For instance, in the final ritual which calls for players to make tests, assuming they've done what they can to perform the ritual, it's still going to succeed, the plans are in motion, but the consequences are extra corruption to the players, or perhaps once the shift has occured the planet has suffered major damage they will take more effort to repair. Perhaps, if they fail exceptionally, most of the population that does survive is now a bunch of gibbering mutants with little to no coherent thought, so now the factories have to be repopulated after dealing with the left over dregs. Major characters to the story would obviously survive, with some alterations.
Lots of people seem very hung up on the idea that a Chaos Space Marine would stand out too much even naked and chained as a prisoner. Well, I'm pretty sure your average imperial citizen, even IG, wouldn't recognize a naked space marine right away. Sure he stands out, but so do all the goliath, mutated, cyborg monstosities. For added fun, maybe one of the wardens does recognize a space marine when he sees one and tries to get some answers. The other alternatives in the book are just as cool though.
Let me know what you think. And if you're on the fence about getting this book, Let me say I was not dissappointed.