I haven't finished the entire game, as I still have Terra left to do, but all the heroines are finished, and I doubt my opinions will change after the final route, if I read it.
I should mention first hand, that a non-happy end diminishes my opinion of the route, in all games. So some routes I dislike because of an ending, others may like.
Common route: Best part of the game, although I'm sure people will disagree with me. It's not as good compared to the common routes of other Key titles, but it's fine. It suggests a lot of potentional to the game, and does a good job of introducing the characters.
This is the most galge-ish route, which is strange, considering it's written by Ryuukishi. The route was good for the most part. The frequency of changing perspectives was annoying. The unreliable narrative didn't really bother me. I didn't much care for Lucia before doing this route, but she was pretty moe in it. The date scene with Kotarou was just the best. The way it went though, the ending and all that, I thought was bad. I don't think it was cool to have Lucia's poison kill all those people, and then the part at the mall was just awful. But the whole 'mystery' part leading up to that, was great. The route should've ended after the date. One problem people might have, is that this route really clashes with all the other routes.
Probably the most actiony route. Chihaya was my favourite from the trial, so I went with this route first. The only time I felt my eyes water up was during this route. It felt the most like a light novel written by some high school kid, but that was alright. Sakuya is a cool character and helps make the route more enjoyable. It also had a happy end which is a plus. I didn't understand Midow. He seems to be given far more importance than he deserves. He had a fight with Kotarou in the school. That's cool, but so what? Then there is the whole thing with him talking to Kotarou in his mind, but it just seemed silly. The route dragged on a bit at times, the fighting scenes weren't as thrilling as they could be, and there was a serious lack of romance between Chihaya and Kotarou. I would've at least liked to see them kiss. Oh well.
Too lacking in content. The route didn't really have much of an impact on me. The first half of it severely dragged on, and felt like a poorly done moege. Kotarou didn't really do anything important. The ending was kind of shitty. Shizuru is cute though, which is good.
Far too wordy. I really don't like Romeo. There is way too much filler text, and the route probably could've been half as long as it was. In fact, it should've ended with the Key being killed in the forest and then Kotarou and Akane living happily ever after. But instead we get such a shitty end, but some people like that kind of thing.
Absolutely no substance. It's also the only route where Kotarou's problem with his head is mentioned and seems to play any kind of role, which was weird to me. The route was probably about 4 hours long, but felt like it had 1 hour of content. I learned interesting stuff about Kotori's past but that's it. And what was with the ending? What the hell? Kotori doesn't come to see him in the hospital, so I'm expecting something to be up or that there is some kind of reason, but it just ends.
Moon: Easily the worst route. It felt like a farce. It's like plot twists for the sake of plot twists. I don't recall there being foreshadowing about the moon. I also don't understand how the common routes lead into the Moon route. In Little Busters, Refrain unlocks after finishing all the girls routes. But it makes sense.
This Moon route, it's kind of hard to describe it, but it felt like a Dragon Ball Z movie. A self contained story, not particularly a great one, with no relation to the main series, quick development of events, all your favourite characters showing up, cheap action, etc. I didn't know if I was supposed to take it seriously or not. Was I supposed to be upset when characters were dying? Or was I supposed to laugh at the absurdity of the situation? I was half expecting it to be some kind of prologue and the real Moon route to start.
I've started reading Terra as well, but I have very little interest.
What the hell is with Mappi or whatever? Who thought up that garbage? It is the least fun interactive thing I can think of having played in a VN.
One major annoyance, was the lack of stuff that seems obvious to me. It should've been full voiced. It's really distracting when some minor characters have no voices during dialogue. It should have had more character sprites. I do not understand why characters like Inoue do not have character sprites. And finally, the lack of BGs. There were too many scenes that just had some generic background cg, or no cg at all.
The game seems like a mediocre chuuni game disguised as a galge. I don't understand the purpose of the three writers. They all seem to clash. The characters change too much during routes.
In Chihaya's, Kotarou never kills a single person, and has a very strong hesitation to do so, but in Akane's route it seems like it's the most normal thing in the world for him.
And in Chihaya's route, Kotarou is insanely strong at the end, but in Kotori's, and even Shizuru's somewhat, he is insanely weak. Like he has forgotten he can strengthen his own body or something.
It's also, way, way too long for what it is. There is way too much text that does not need to be there and does not add anything but artificial length.
It's not like I'm a Key fanboy or anything. The only Key works I really like are LB and Kanon. I just think this is a disappointing game. I was expecting more after the trial.