Eps.1-9 are quite a nice, likeable show, if you can stomach some unfortunate but harmless loli-pandering. ("Loli" = "lolita complex", i.e. the anime's occasionally suggestive about sexual stuff with very, very underage girls. About ten or eleven years old. Nothing happens, but the show's still winking to a target audience that needs locking up.)
After that, though, eps.10-12 get enormously silly and can't be taken seriously at all. Occasionally, they might avoid being stupid. That's the best case scenario. Nothing bad will happen and you won't get arrested for watching it, but it's eye-rolling.
The show's hero is Kyou, who's theoretically in high school. I say "theoretically" because he's initially a hikikomori. He almost never leaves his house. His classmates don't know his face. He's pathetic. He spends all his time writing music and uploading it to the internet, then his online collaborator, Kiriyume, will draw illustrations. (Theoretically, he's a hikikomori because of past trauma, but that's one of the more risible pseudo-traumas you'll see.) One day, though, Kyou gets an email from a fan who wants to meet him. He ties himself in knots wondering about this, but eventually accepts and waits in a park wondering whether to run away.
This fan is Jun, a musically gifted orphan and guitarist. (She's very shy, though.) Jun and her fellow orphans, Nozomi and Sora, drag Kyou back to their orphanage (a church) to form a band. Kyou will write the music and the girls will perform. They also have a deadline and a reason to care about this.
This is nice. Kyou tries to help the girls, but of course he's in no position to tell them to go to school and start talking to their fellow students. This becomes a growth experience for everyone. Even if I think Kyou's a twat for skipping school for months, I respect his courage in going back. There are other characters (Kyou's weird younger sister and a mildly tsundere classmate of Kyou's who also lives at the orphanage), but the band is where it's really at. The show takes it seriously. The girls can sing and play very well, but they've never done so in public and they've no idea about how to go about attracting an audience.
The loli jokes won't make you burst a blood vessel. Kyou is annoyingly aware of potential sexuality in ten-year-olds, to a degree that's asking for a slap. He'll overreact in pseudo-comedy fashion. (He's not aroused, mind you. He's frightened that someone will see them, misunderstand and mistake Kyou for a paedophile.) There will also occasionally be suggestive dialogue that's not what it sounds like, and/or family-friendly shots of children in the bath. A normal person wouldn't realise that dodginess could even be perceived here. That said, though, Kyou's sister Kurumi (also aged about ten) is mildly annoying in her clingy attachment to her big brother and tsundere-jealousy. "As a special rule, you're not allowed to get married."
The only thing I disliked here was the English Grandfather Episode (ep.6). The episode's theme is "putting feelings into words", which is expressed through both songwriting and the big question of "should you abandon your friends and go to live in England with grandad?" I dislike how it's handled. To me it felt shallow and clumsy, turning the characters into idiots for the sake of a badly explored issue. Practicalities are avoided, e.g. "can you speak English?"
After that, the show becomes harem nonsense. This is never great, but everyone's ages make it particularly unwelcome here. Another little girl shows up, you see, and she's a prickly, high-handed bitch queen who'll announce that she's Kyou's wife. If he doesn't follow orders to the letter, she'll assume that "I don't matter to you at all!" Admittedly, she's had a semi-tragic upbringing that explains her inability to get along with people, but that was silly too. Is this the 13th century? No. Idiots. In short, she's an abrasive harem cliche and she pulls the whole show into acting and thinking more as she does. Kurumi gets competitive. The girls go on "dates" with Kyou and so on. (At one point, Kyou admires his non-wife's decisiveness. That's one way of putting it.)
It's too surreal to be offensive, though. It's just daft. Small children act like idiots and Kyou's a wet noodle who doesn't tell them not to be silly.
I liked this show best when it was about the music. That's how these fairly damaged people are helping each other move forward and heal. Lonely people lived in their own worlds and didn't know how to interact with others, so it's nice to watch them realising that they needn't be like that. I enjoyed this show. I'd even sort of recommend it, but you'll have to forgive some extreme silliness and it might be worth skipping the last three episodes. (Well, unless you enjoy shaking your head at tripe.) Some people have called this show annoying and even shameful. I wouldn't call them wrong, but there's plenty of warmth here too.