I have read quite a few books by Tim Curran that have been published by Darkfuse and elsewhere and, with the exception of Long Black Coffin, also published by Darkfuse, which I felt was perfectly done at novel length, I prefer his novellas. I think that is because of the types of stories that he writes.
Intense, non stop action. Horrific imagery. I feel that these types of stories lend themselves to a shorter format because if stretched to novel length, what is horrifying in a tight novella, wears down the reader and dilutes the tension. I do agree with other reviewers who state that Mr. Curran gets repetitive. I will say that I have only found this to be the case in his novels (for example Hag Night). His novella Sow is probably the most horrific possession story I have ever read. Headhunter is another recent example of a really well done novella. I could name others. Practically all of his novellas actually.
The plot has been outlined numerous times already so I won't get into detail other than to say that a really creepy idea for a story became diluted and repetitive in novel length, mainly because character development remained minimal and there is really nothing going on here other than nonstop action.