This is my rant review of Little Busters!
I will start with an introduction to the typical formula for a Key VN adaptation.
Little Busters!, like Air, Kanon, and Clannad (and Clannad After Story), is a visual novel adaptation. Unlike visual novels, anime cannot take a specific routes and then restart to try another. Successful adaptations must somehow combine scenes from all routes and have an overall conflict, in addition to the subconflicts in each arc.
Kanon does this by combining Ayu's search for a lost belonging with the problems of every other damsel in distress heroine. It does have quite a few romance scenes with heroines other than Ayu (maybe more), but overall I accept it because it shows what the visual novel is like. The humor is interspersed evenly throughout the series, and it maintains the reader's interest. (One thing going for the series is that Yuuichi is the only main character of all Key works that doesn't have a tragic past begging for pity.)
Clannad takes the format of Kanon, and makes it better. It starts off with the basic conflict of restarting the drama club. In addition, both Tomoya and Nagisa have flaws in their character, allowing room for character development. (Yuuichi barely changes throughout the entire series.) Then, as heroines are introduced, their problems are brought up and solved, like in Kanon. However, instead of completely disappearing (like in Kanon), the characeters still have some role in the plot. To justify romance scenes with girls other than Nagisa, the story is written so that all the girls (except Kotomi and Fuuko) have fallen for Tomoya, and they give up later in the series. (One bad thing about Clannad is that Sunohara is just an excuse for slapstick comedy. It's funny when he is beaten up, but that's usually all he is there for.)
I'm not going to comment on Air (as no matter what I say about it, my huge bias against it would affect my statements; also I never played/watched videos of the visual novel).
Now, let's take a look at Little Busters! I played the visual novel and loved it. I watched the anime and...well "hate" is a strong word and wouldn't be accurate but...I guess I was very disappointed. Even more disappointed than Umineko no Naku Koro ni.
From the onset, the only objective of the protagonist and his friends is to create a baseball team, which is (more or less) accomplished halfway through the season. Every person they recruit has some sort of problem in their lives. (Who didn't see that coming?) Some problems are realistic, some...not so real. As much as I love Kud's arc, I have to say the conclusion was the biggest (and fastest) Deus ex Machina I've ever scene (and also the VN version was 1000x better/dramatic). Even bigger than Kirito in Sword Art Online (and that was a big one). In typical Key fashion, a characters' problems are resolved, and then she fades away (to varying degrees depending on which Key work you're referring to). All heroines come back for the filler episodes, but then disappear again whenever the story beings another heroine's arc. Sure, in a VN, it makes sense for other girls to disappear, but for an anime, YOU CAN'T DO THAT! Look at Clannad. They did very well in having heroines take on supporting roles.
Also, there is no romance. Zero. Little Busters! is the same type of VN as Clannad. Clear all the routes to unlock an epilogue arc. "Clear" meaning "conquer" every girl (as Katsuragi Keima would put it). While I don't expect Riki to create his own harem, I felt something missing in LB. I do realize that focusing romance on a single heroine is impossible like they did with Nagisa in Clannad (can't explain that to people who didn't play the VN, because it would be a spoiler), but I did expect signs of infatuation, because the way the anime is right now, it feels like I'm watching a totally different story. I think the reason no romance lowers the quality of this anime, is because the way it is now, Riki just feels like someone who is just looking for problems to solve (and for some reason, he is the only one who can). Having some romance would make a little more sense. If the girl likes the guy, she will trust him and ask for help from him. It would seems natural for the guy to do everything in his power to save the girl. It would also seem normal that he is the only person doing anything about it.
Also, some of the jokes are poor, some are repeated too often, and some have bad timing. Some episodes are meant to be 100% comedy, while others are 100% drama. While it is good to maintain a serious mood in serious times, I don't think viewers should be able to say, "This episode started with Masato being socked in the face, so it's going to be a funny episode," or, "This episode started off with a depressing flashback, so it's a serious episode." In other words, episodes shouldn't be classified into serious or funny. In my opinion, many of the funny episodes are unecessary, like the test of courage and the slumber party. Sure, they were fun in the VN, but in an anime adaptation where episodes are limited, the story should spend more time on covering the heroine's arcs than silly side stories.
I will mention one thing JC Staff did right about the story. That's right, folks. JC Staff actually IMPROVED something!!! That is: Komari and Rin's friendship is emphasized more than in the VN, and what a beautiful friendship it is. Note: I'm not saying KyoAni could have done it better than JC Staff. In fact, it's completely useless to argue that KyoAni could've done better, because no amount of protesting will change the fact that JC Staff is making the show.
Animation quality is nothing special. Some scenes (very few) are done very well, especially for the last few episodes, while others are evidently drawn with saving money in mind (a lot of them). JC Staff was probably thinking: "This story was made by Key, so people won't care how well we animate it, and it will still be a success." Well they're wrong about us not caring. Based on BD/DVD sales, it is somewhat of a success, which is both good and bad. Good because it means Refrain will be animated into a second season, but bad because it's like rewarding them for doing something wrong.
The opening has a unique start, but turns into something generic. The dramatic build up in the song just isn't there. I liked the VN version of the song much better. Background music is pretty good, except for the fact that some tracks are overused. The ending is boring (never liked that song for some reason), and I've only listened to the whole thing a couple times.
There aren't many places for voice acting to stand out in this season, so I can't really say much about it. It's up to par with the VN (same voice actors so that makes sense), and tones are realistic, I guess. I'm not really expecting much regarding voices until the Refrain arc (the epilogue arc), when there are some really dramatic scenes.
Riki is a two dimensional character. I would go so far as to say he is boring. So is every other member of the cast. Some are likeable, but they are all flat. The development of Riki could have been done a little better if they hadn't tried to follow the VN so closely. Unlike the VN, Riki should have grown with every experience. (VN's have the player play one route at a time, but the anime is a linear story.)
In the VN, Riki's development is only visble in Refrain (which is very long). It is impossible to have significant character development in the VN, because each route is related to each other in a special way, and the order of routes taken is determined by the player. Thus, if route B has more character than route A, and the player chose route B before route A, that would cause problems with continuity. To those who haven't played the VN: Turn your brain off right now. I said that to make a point, but if you keep thinking about that "special way" the routes are related, you might spoil yourself.
Anyway, back to characters. Every heroine has her problem solved. Masato is a muscle maniac/idiot. Kengo is a loner. Kyousuke is a charismatic but random leader. None of them really develop.
Rin is probably the girl who shows the most change. She changes from shy to somewhat socialable, and even the viewer slowly gets to know her caring nature more throughout the series.
It's tough to remain objective on my rating of this show, considering I loved the visual novel. I really don't think Little Busters! was meant to be made into an anime. If I hadn't played the VN, I'd say the story is a meaningless slice of life anime with flat characters. The animation and voice acting are acceptable, but that's about it. Would I recommend this anime to others (who haven't played the VN)? No, unless you desperately want your fix of dramatic heroine arcs made by Key, and have already seen Air, Kanon, Clannad, and Angel Beats. To those who have played the VN, I would say it's interesting to see the story you read animated, but the outcome is depressing. I would recommend it, but don't go in with high expectations.
Note: My opinion on whether or not I recommend this anime may change based on how the second season goes. (I'm assuming there will be one, or this truly will be the worst adaptation in history.) However, my opinion on the quality (story, animation, sound, and characters) will not change.