Riki was a child when his parents died, leaving him hopeless and depressed. What saved him was a group of four kids calling themselves the Little Busters. They took Riki out and played with him during his time of need. He really enjoyed being together with them, and his grief gradually faded away. Now in his second year of high school they still hang out, fight and live together, and enjoy their school life.
True friendship and growing as a person(9.5 of 10)
This is review about season 1 and 2, because you have to watch both to feel the emotional impact. Basically, the first episodes begin with a hilarious comedy with the heartbreaking moments and past scars increasing with each episode until one arc is over. Especially, the last two arcs(Haruka and Kud) where so impressing and touching, but maybe due to the lack of OST timing one step was missing to make me cry. However, after overcoming so many hardships and growing attached to your characters, season 2 comes in. Even if there are people saying storytelling and tension of season 1were nothing special and impressive, most of them will agree that season 2 is on a whole new level.
Little Busters! began with the question what you would do after school time is over and all the people dear to you might vanish from your life only to realize with season 2 that the intension of the story was more meaningful: What limits are you ready to break to help your friends ?
Characters and their behaviors which seemed plain in season 1, will shine in season 2. Most noteworthy for this character development would be Masato, seeming like the Sunohara of Little Busters!. But, with the context of season 2 you will see there were reasons for his behavior and that he might be the strongest of them all, not only physically. Of course, all the others of the Little Busters(especially the old members) have an amazing development as well(oh, you will really like Kyouske's development), but it would be better to see it for yourself. With season 2 the timing of OST was also corrected: Although they use the same OST as in season 1 they know when to use is it now. I don't know wether it would have had such an emotional impact on me if there hadn't been Soundtracks like: Song for friends and Faraway. Jun Maeda is a genius and quite a sadist(look for the meaning of the lyrics after watching the anime and you will see he perfectly summarized the whole anime, with all his compositions, especially with the 2nd op)
"In short": Of course, it has its flaws like: some questions being left unanswered for anime-only viewers(e.g. Why does Kengo get so emotional when he sees Miyuki again ?), the lack of romance(e.g.the really open confession of one character: like he/she thought: We are from opposite gender! Hell, why not ?) and the fact it has only 13 episode.^^ So why 9.5 of 10 you ask ? Because when it is good, it is good at an extremly high level(characters, OST, plot, tension, emotions and everything else I have pointed out) and that overweighs the flaws greatly. Furthermore, the animation studio was clever enough to realize that the main meaning is about friendship and thus being able not to give this anime a feel of a dating sim. I also liked how they were able to create this tension and emotions with cliffhängers and turns building those emotions up towards the final episodes where you finally break down with your growing attached to characters.(The voice actors did a really good job here).Even now when I know what is going to happen, the emotional moments of season 2 haunt me and not many animes or other media can do that after revealing the whole plot. I have looked for an anime which could proof me that I didn't become emotionless as I was not on the verge of crying when I saw the final of Anohana^^. In fact, the last time felt such an emotional impact from an anime that I could not sleep from overexitement and sadness for a few days was, when I watched Angel Beats' final and one certain episode of After Story. This is definitly an anime that can compete with Clannad+After Story.... No, I would go even farther: Little Busters! + Refrain is the best work of Key Animation so far.(The animation studio did also quite a good job adapting this visual novel, at least from an anime-only viewer's point of view)
To end this really long review, I can only say: Omega good job, Key Animation !!!