Zankyou no Terror may be worth watching if you’re a fan of Death Note and/or similar anime. However, while the art is fantastic, the story seriously drops off at the half-way point with the introduction of a certain character. The premise that is revealed later in the show, along with Five, feels quite tacky and really undermined what I thought could have been a really interesting and cool show. Zankyou no Terror has the looks but not much of a personality.
The show has some decent characters, personally I liked Nine and the dynamic that 9 and 12 had with both the detective and schoolgirl. Overall though, I felt like Zankyou could have been so much better if it went into a different direction plot-wise that supported its themes better. The things they want to say were left half-done it felt like. Certain other plot elements felt weak and underdeveloped as well(the ‘game’, for example). I ‘get’ it, but the manner in which they go about their mission seems pretty ineffective at actually accomplishing their goal…something that turned me off of the series when I was finally done. All in all it felt very…postmodern, if I had to use one word to describe it.