Black Bullet is fairly fast paced. Thirteen episodes, the plot develops acceptably reasonably, there's not too many deus ex machina moments that make you go "Which hole did that plot-device come from?" Although there are many moments that I feel like should have been completely taken out or required more explanation. Take for example, the ending of episode four. I was thinking about that for a good couple of hours, yet I got no closure on what happens, because it's never brought up again.
Anyways, I rate on enjoyment. On the wonderful rainbow scale of enjoyment, I gave Black Bullet an 8. Quick synopsis.
Story: Fair (6)
Post-apocalyptic, sci-fi. Humanity is on the brink of extinction, all that keeps them alive are gigantic monoliths of Varanium, which repel the Gastrea. Gastrea are (typically insectoid) monsters that can infect humans but mostly just butcher them into horrifying piles of blood, corpse, or just eat them. The combination of zombies, insects, parasites, vampires, and something that regenerates extremely fast.
Art: Very Good (8)
I don't know, I'm not critical about art. It was nice, I recognize the characters. Very gory, too.
Sound: Good (7)
Epic battle themes, epic opening, melancholy ending. Fits the show.
Character: Good (7)
Got your typical characters, makes for a full house. Tsundere, yandere, plenty of lolis, and a kickass protagonist. Personally I do not think of any of them as basic or generic, because I do deem them to have unique flairs, if not an insane amount.
Enjoyment: Very good (8)
Short series, about 3-4 days if you're casual watcher. Enjoyable at the least, unless you're a technical detail nazi who checks for everything and hates everything.
Overall: Good (7)
Fix a bit of plot holes (Smashes holes into immortal snail mutants, crushes walls, jumps across roofs, cant break through the grip of two generic thugs) and plot twists that have nothing to do (episode four I'm looking at you) with the plot. More episodes are needed, the story is underdeveloped and a lot of scenes from the ending are completely unseen in the actual story.
