For a deeper in-depth review, read further. Be warned, there are spoilers.
Mystery. To start, the mystery is horrible. I picked this anime up hoping to find a nice mystery anime. Technically it is a mystery anime. But it's executed in such a fashion that it doesn't at all feel like a mystery anime. When you watch a movie like Se7en, you're really engaged because you really want to know who did it. When you watch Sherlock Holmes, you find yourself drawn i, despite the fact that you know the bad guy is Moriarty, because you want to know how Sherlock solves the challenges thrown at him. Gosick offers none of these. Any plot twists it "purports" to have is easily deduced. I could see who the villain was coming a mile away. Everything was so blatantly obvious. Granted, I didn't always see how the "villain" executed his or her plan, but that's because Gosick doesn't offer clues here or there. The main female character jumps in like 10-15 minutes before the episode ends, spoon feeds you the solution, without really explaining how she managed to deduce such a solution, using clues that seem nonexistent or clearly bullshit (please see motorcycle incident with blood girl for an example). I guess my biggest grip is yes, technically, Gosick does offer these elements. It just executes it in such a poor fashion it's like you're NOT watching a mystery anime.
Male Lead Character. This guy is annoying, horrible, does not grow at all, and is as flat as a cardboard. By the end of the show you'll want to punch him in the face. He incessantly screams out the female lead's name to the point where it's like the creators are purposefully trying to tick you off. He's also very unrealistic. I understand he's like around the age of 18, a high schooler, but are you really to expect us to believe that he doesn't know what love, or at the very least, what liking someone is? He constantly refers to the female lead as his "friend" and justifies why he does what he does because she's his friend. Except he has other friends, and he doesn't risk his life for them. Either make it so he's all shy and can't confront his feelings, or make it so that he acknowledges it but he can't confess to her, and or make it so that he knows he likes her and he tells her about it. None of this "I totally risk my life for you, I think about you all the time, I love hanging out with you, and there's obviously chemistry between us, but we're totally just friends."
Female Lead Character. She's mediocre. To say she's bad would be a slight overstatement. My biggest gripe with her is her "deductive" abilities, but I think that's more a flaw of the plot and story than the character herself. She does show growth, and she is cute. But that's about it.
Music. Didn't really stand out, and not even in a way where the music is so good it allows you to really sink into the anime, not realizing you're watching an anime. Long story short, the music is average. It's like elevator music that you don't enjoy, but don't hate.
That Guy with the Pointy Hair. A slightly below average character. His change is gradual, and you start to see it, but then it's like the creators realized they only have 5 episodes left, so they put his character growth in overdrive and suddenly he's changed too much, too quickly. I see where they were going with him, and I appreciate it, but they executed it in a poor fashion. Either initiate the change earlier, spread the pace of the change so its slightly quickened across the show, or make the season longer. His change came too quickly, too abruptly, and you know it all happened because the show was ending soon and they needed his character to perform some task for the show to end the way it ended.
That Really Annoying High School Teacher. The high school teacher is 110% extra and useless. I understand she's comic relief, and sometimes we include comic relief characters that really don't offer anything. They don't move the plot forward, they don't stimulate character growth, they really don't do anything but offer the occasional laugh. And while that isn't ideal, that's okay and still acceptable. But the high school teacher wasn't funny. She never was. She was actually annoying.
Other characters. Everyone else was okay, but no one stood out. Gun to my head, the short haired blonde girl was the best character. But even she had a flaw, namely that it was implicated that she was the perpetrator of a certain murder, except the show never followed up on that, and just pretended like it never happened. It's one thing to find out she wasn't the murderer, and that all the signs were just a coincidence. It's another thing to drop the matter entirely like it never happened. Either don't give signs implying she's the murderer, or at least conclude the matter.
Ending. The ending was overly dramatic and quite bad. The whole point of the prophecy was that... get ready for it... it's a prophecy of the future, an inevitable fate that cannot be avoided without some significant fight-back. But nope, they just drop the prophecy like it's nothing, and then prove it wrong with little to no effort. You can tell they threw the ending in just because they wanted to end the season on a dramatic and epic note. Except it felt quite out of place. The ending wasn't that bad (except it was executed poorly), it's just that it came too quickly. Once again, it's as if the creators realized they only had 3 episodes left to conclude the show, and thus put everything into hyper drive.
Verdict. Unless you've depleted all other mystery/romance anime, I don't see why you would ever want to pick this up. It's a mediocre anime flirting on the skirts of "bad anime."
