Vampire Siege at Rio Muerto is a gripping, fast-paced, suspenseful tale with well-developed characters and an interesting plot. The story, a mash-up of the Old West and horror genres, contains several fascinating twist and turns, and the ending took me quite by surprise while remaining organic to the plot.
Whalen makes good use of foreshadowing as he tells the story, letting us know at the beginning that Don Pedro can't be trusted, but without revealing the full truth of his character until the final chapter. He also hints at the final fate of several other characters in a way that keeps the reader in suspense until the last possible moment.
The characters themselves are well-crafted, with just the right amount of information revealed about each person at just the right time. Mordecai Slate is particularly well-written, being relatable yet distant. He is someone the reader can trust, while still keeping a few secrets.
The story does contain frequent use of alcohol and tobacco, some language, blood and gore, and occasional references to sexual immorality, but those things are not graphic, nor do they take center stage. Rather, they contribute to the lawless setting, the dark character of the antagonists, or the suspenseful plot.
I would definitely read this book again, as it was the first book in several months to really hold my interest. However, I would recommend it only to mature and discerning readers, those who can focus on the strong good-versus-evil plot and engaging characters rather than merely dwelling on the elements I listed in the previous paragraph.