Feels like a gamble whenever I vote for something recently but a "Meh" seems "Fair"...
Let me start by saying that technically the show is good. The cold look goes well with the theme, the animation is good and the music (when it's not overdone) too.
Unfortunately this all means nothing when the script doesn't hold up. For a show with "Terror" in the title... this isn't seen here. Yes, buildings get blown up but that's about it. The already short season spends it's time with solving riddles for clues about the next bomb's location instead of anything meaningful. The master plan the 'terrorists' have come up with is really one of the worst ways to go about it and they're supposed to be exceptionally smart.. Lisa, a girl who gets involved with the group, is one of the worst characters I've ever seen. She hardly has a personality and serves no purpose except to bringing trouble for the protagonists. Seriously, just by removing her they would have had already more time for characterization or backstory. Heck, removing the 80% that is spent on riddles would have allowed a much different direction and actually doing something with the premise.
As much as I was looking forward to it I didn't care for most of the episodes and given it's conclusion I wouldn't recommend it.