I have just recently finished my second reading of this book cover to cover. And I will admit, there are some interesting ideas. Some of the archetypes and class options offered are interesting.
However, nearly everywhere else in the book, the material falls flat. The primary selling point for me was the corruption system. Suggested as a way to finally be the monstrous characters we all wanted. This is a bad system. Let us imagine that you use the provided variant rules for a more gentler, more kind version of the corruption rules, your character still faces severe penalties by the corruption system as default that far outweigh the benefits. The worst part? You don't even become what you're trying to.
The closest you can get, to say, a lich, or a ghoul, is an approximation of weaker versions of their abilities without a true type change. This is, in and of itself, unacceptable. There are feats that have more effect than this, and frankly, it's more confusion, more trouble, and less benefit than simply offering my players to take the template they're after.
Finally, due to a little sidebar on evil spells, I find the recent shift in the approach to good and evil alignment to be stagnant. Thanks to the stated rules in a sidebar, casting an evil spell, is an evil act, regardless of why it was done. Therefore, by simple logic, no matter how flawed it seems, using a good aligned spell to evil ends, is also a good act.
Ultimately, if you're a first time DM or player looking for some tips on playing a horror game, or want some interesting archetypes, it can be useful. However, if you're like me, and you were looking for meaningful character options, I don't think you'll find many good ones here.
