Story 8: First of all, story isn't bad just because you don't like it or agree with it's flow, it could be bad if: there wasn't any real story or nothing interesting happened, it was confusing and\or some things weren't explained or it had a lot of plot holes etc...And School Days wasn't any of these. Story is very simple, without any time skips or big flashbacks, there wasn't any mystery or a reason for you to overthink anything, it is straight forward. It is usually told from Makoto's point of view. It gave a lot of time for Kotonoha to go from hard to get, to a girl who is madly in love with her boyfriend- Makoto, it also gave Sekai enough time to develop jealousy so it isn't rushed and it also had a very few unimportant moments. Almost every event is there to make motive and preparations for THE ending.
Characters 6: The biggest problem of the series are the characters, and it isn't because they aren't the most noble persons ever, it's because they don't have ANY background stories and so they usually lack motivation. Love is acceptable motive till one point, but you can't love that much someone, whom you met a month or two ago, and this goes for entire female cast. Makoto, probably the main reason why so many people hate School Days, on the other hand has good motive, he is a guy, who can sleep with a big number of girls and he accepts the offer with his hands wide open. And he was a refreshment because in anime you barely ever see a male character who is douchebag and who is playing with girl's feelings, while female cast is somewhat original. But I really felt like Makoto was made for the sole purpose of being hated, same as Sekai, while Kotonoha was there to be pitied, and on the end Otome is the only person who has somewhat good moral. But I liked the fact that characters have bad personalities and they tend to think only about them selves, because in reality people are that way.
Art 8: Nothing overdone with a lot of details but enough to express people's emotions on their faces. It has a small and dull choice of colors which are matching with the atmosphere of the show. Characters more or less look alike with exception of Kotonoha's design who isn't just the most beautiful, but she also has the most details.
Sound 8: Opening, even though nice by itself, is too happy for this sad series, but the ending is beautiful and it goes perfect with the the dramatic ending of almost every episode. The background music was always matching the scene but it was never something that you would listen on it's own. The voice acting was done pretty well.
Enjoymen 8: So this is the part where you can grade series bad just because you didn't like it. But I did like it, in most of the times I was just giggling because of the wrong life decision someone would make, or because of the irony of some event, and I usually like anime with characters that aren't antagonist of the series, but their personalities are disgusting, it makes them much more realistic. This anime is very easy for understanding so it's good for watching even when your concentration is at low level.
Overall 8: It's not the best anime ever made and it does have its flaws, but it's one of the most realistic series, till one point, and I can really connect some characters with people I know, it's point isn't fighting evil and saving world so it's not as stunning as some other anime are, but it has its story which is never misled and, if anything, it is worth watching just so you can see the ending.
