I like it so far, the music he was composing really has reminded me of the login theme from Mabinogi. I don't think they copied it at all (the two pieces really are not that similar at all), I just thought it was nice.
Rock music & imouto's piano so much better than that rockshow (fukumenkei noise).
They're cute but quite tropey. Goto's va is fine but pitch too irritating. More interested in the blond drill classmate, seems like an unusual loner.
His upload probably refs Miku's deep sea girl.
I like the idea of a hikikomori growing his character as he uses his talent to help out a charitable institution. However, the loli three main characters aren't even one-dimensional stereotypes. They can clearly sing, play instruments, and even write their own music. The episode really needed to establish why they need him during the first episode.