I'm a Mignola fanboy so my review will be biased.
Man, I've been reading BPRD for a while and it feels so good to see Big Red and also do some one and done issues. With BPRD going full steam ahead with world building and character buildling (not to mention monster fights) it's been a while since I've read HB just walk into a situation unprepared and beat the shit out of weird folklore, mythological monsters. This is what it was that hooked me on the Mignolaverse:
World: Not a lot of world building, all of of it is done in service of the title and the setting of the stories. We travel all over the place with this arc, from Italy, American South, Caribbean...just all over. The art is all over the place, with different artists taking different approached on telling a HB story, and of course there is the wonderful Mignola illustrated Temple of Moloch. As I said, the world building is minor, serving mostly the tale that the writer is telling, but man is it ever cool to have a monster of the issue books again. I especially liked the setting of The Crooked Man as it is a world and lore that I am not too familiar with and it made for a very fresh read.
Story: One and done are great when you just want to throw multiple ideas and stories towards the reader. These tales are simple, paced well and fun. There are still hints of a darker grander arc that will be for Hellboy but mostly this is just a collection of him doing him: Being called in, running head first, getting the shit knocked out of him, then hitting hard back. It's fun, the dialog is crisp and glib it's just fun. I especially liked Crooked Man and for some reason the Mole. Crooked Man for the unfamiliar terrain that I get to experience plus the super odd and unsettling art style, while the Mole is just ridiculous and the art made for some panels that made me smirk. Good fun!
Characters: Not a lot in terms of character development, but wow we got a whole slew of characters introduced (for one and dones) this time around. All are bigger than life, odd and just interesting. The Crooked Man was interesting as was the witches in that tale. I also really like Blackbeard as I found him utterly ridiculous. It's a fun collection of characters you'll laugh and smile at, see them die and have fun reading it.
Nothing too deep this time around, just getting back the essence of HB single issue books. Fun, short, well paced and him beating the shit out of monsters. What more do you want?
Onward to the next book!