Shredder has a decent narrative flow, but strictly B-movie military action/slasher/horror plot and tropes. Tough ex-colonel, drinking to forget his past, is thrown together with a team consisting of macho-girl and sexist shmuck for usual banter, a religious convert, a strongman, all phenomenally skilled, tough and cocky. They are sent uninformed, and stupendously under-motivated, to eventually face all-but-indestructable, overwhelmingly lethal alien/demon... Couple more cliches (evil weapons dealer, etc) round out the plot. And, as noted elsewhere, lots of gratuitous, well-over-the-top gory violence -- but all with a rather pale, video-gamey quality that left me skimming rather than disturbed.
Decent, if unoriginal, scene writing, mostly acceptable dialog, with one or two howlingly bad breaks: Yes, in the middle of a zone of carnage, let's sit down to hear the backstory of... oh wait, we already read this in the opening scenes -- why are we "explaining" it here??? Generally, the book moves and reads quickly though, with verisimilitude as defined and limited by the genre: E.g., somebody who has been both eviscerated AND vivisected manages a final pithy bon mot (mal mot?) and knife thrust.
However, even if you don't mind the gory mind-candy, don't read this if you are distracted by grammatical errors, especially gratuitous changes in tense from line to line. Also some decidedly strange idioms like "Ruby is sat next to..." I was somewhat jarred and pulled out of the story a few times, and yet not so badly that such structures really ruined the story.