I think I'm too burned out after seeing the DC Universe destroyed by zombies in DCeased and its many spinoffs to really care how vampires go about their take on a horror apocalypse. These sort of "What If?" or "Elseworlds" or "Imaginary Stories" always lose impact since they don't count in the DCU continuity.
I mean, if DC thinks everyone just wants to see the superheroes die page after page, why not go full "Faces of Death" snuff film and put out a book that just consists of pin-ups of all their characters being murdered? Get really gruesome and tasteless and have a "Capital Punishment" special that has everyone being executed by hanging, electric chair, firing squad, etc., etc., ad nauseam.
More specifically to this book though, the art is a little too cartoony to convey much menace or horror. Characters are thrown in by the dozen without showing much personality or even being named. I'm annoyed that for some reason, Barbara Gordon's Batgirl acts like she's a little drunk or high throughout the whole book. What's up with that?
I have no enthusiasm for picking up the conclusion right now, but hey I might click on it if it turns up my in my library's catalog. I'm a real sucker that way.