Fridge: Ore no Imouto ga Konna ni Kawaii Wake ga Nai!
Not once does anyone, including most of the fanbase, question Kirino's sexuality, only whether she has a complex about her big brother or not - even though the activity that kicks the whole story to a start is playing erotic games that focus on pretty girls
I do! I do! I think she's bi.
Uhm, I play erogames, too, and the moe can be pretty much nonsexual. It's clear that Kirino wants a younger sister(She became sort of jealous of Kuroneko once), and she doesn't seem to get off on the sex scenes, as it's mostly "Kyaaaa, the reaction from the character was so cute!!!" Rather than: "Hah, haaah... That was hot..". The novel she wrote seemed to be more platonically inclined, as there was nothig hinting that it might be romantic. Though, Bi the Way is a plausible explanation, too.
Dude, did you watch the episode about her playing eroge? She moe-ing over how hot it was (she actually said "THIS IS SO HOT!") so much that her brother barged in on her!
Could her sister complex be explained as some form of subconscious projection on how she wants to be doted on?
She's clearly turned on by women (girls, really, but they're probably not much younger than her) in some contexts. Sexuality dynamics being what they are, she might not consider herself bi due to the whole "I can tell the difference between the 2d and 3d world" thing, but the subtext is obviously there.
Elaborating on the above statement. At one point, Kirino has Kyosuke play an eroge called Sis X Six, featuring two little sister heroines. Kyosuke obviously enjoys the route featuring the more mild soft spoken sister; but finds the other, tsundere sister Rinko, to be far too much like Kirino for his liking. After explaining to Kirino, about how much Rinko is similar to her, and explaining how he disliked that route because of said similarity; Kirino proceeds to launch into a tirade about how Kyosuke doesn't understand the charm of the character which in fact starkly resembles herself...Just to make that perfectly clear, Kirino wanted Kyosuke to like a pseudo copycat of her in an incest oriented video game. Oh yeah, she's projecting alright.
It gets clear that Kirino can be pretty loud when moe-ing over her belove games. Why hasn't her brother noticed this earlier, since its confirmed that he can hear her?
She was probably more careful about it before he found out about her hobby.
(with the provisio that I've only started watching the series) Why is Kyōsuke so submissive to Kirino, e.g. doing whatever she wants, not calling her out for her hypocritical stance on playing H games, etc., even when he has a huge amount of dirt on her?
Because his character is meant to replicate the submissiveness of the moe anime character (think Mikuru Asahina); the type of girl often featured in H-games (with the provisio that I haven't played them very much). It's a massive role reversal and massive ironic twist; it shows that the same traits that some [men] seek in that kind of anime character would actually be really annoying in real life.
She's family, that's why. Two family members ignoring one another for years on end (as Kyousuke and Kirino were at the start) is a pretty terrible thing, especially in a family-centric culture like Japan's. Now that a dialogue has finally opened up between them after so many years, Kyousuke obviously wants to do everything he can to keep it that way. It's not quite a matter of submission, it's more that Kyousuke's trying to make up for all the years that he didn't make himself available to Kirino as her big brother. In fact, Kyousuke has a line in the manga that supports this:
Kyousuke (Internal Monologue): Even if she doesn't like me, or if she doesn't care, or even if she's conceited, rude, and uncute, I have to help my little sister!
This is also supported in the anime itself, when Kyosuke goes to America to get Kirino to go back home, he literally says to her face, he doesn't care of she hates him, he just wants her to be there. Same in the non-canon PSP game, where Kyosuke breaks up with Ayase, and tells her face to face that he prioritizes Kirino over her.
Saori Bajeena. At first she may seem to be little more than a Shout-Out to the alias Char Aznabel takes in Zeta Gundam. Then cut to a scene where you don't see her face and she is flanked by two maids, showing her as a rich Ojou. Then it hit me; Quattro Bajeena was the alias Char used when he joined the AEUG, so that he could hide in plain sight and still achieve his goals. Now replace the goals of showing humanity the error of their ways with; wanting to buy anime, manga and eroge. Saori is being true to her ideals in the same way that Char was. Well played... - GX Next
At first the opening song to the series IRONY by ClariS seems to be the kind of peppy anime song you would come to expect from a genre that shows the Otaku day-to-day life, much in the vein of Genshiken or similar shows. Then when you actually understand the words the song becomes brilliant. If there were a nation for Tsunderethis would be its National Anthem. - GX Next
Kirino is a Model Student, a track star athelete, and has a well paying job, she is everything the stereotypical good girl is. However she is a Literal Closet Otaku, seriously; she hides all of her eroge, anime and little sister items in a secret closet she hides behind a shelf unit.
The reason Kirino could get her first novel published even though she had never written anything before it is because it was pornographic. Or at least borderline.
ManamiTamura. At first people were either cheering for her or criticizing her since she wasn't as remarkable as the other girls and because her defining trait was 'normality'. No wonder a lot of readers/viewers—if not all—were seriously caught off guard by the complete 180 of Manami's prominence in the Kousaka siblings' Cold War and ultimately the indirect instigator of the series itself!!
Another thing worth mentioning is the Odd Friendship she shares with Ayase. Maybe it's because of the Nice Girl tendencies Manami and (occasionally) Ayase share. Turns out they're Not So Different, what with varying degrees of Moral Guardian tendencies and Bitch in Sheep's Clothing attitudes. While Ayase acts out her mean attitude more openly to protect Kirino, Manami prefers the Manipulative Bitch method to subtly talk the Kousaka siblings into changing themselves drastically.
Why is Kanako, despite declaring otakus as weird and/or disgusting, pretty easygoing and accepting when it comes to her cosplay job? It's mostly Hates the Job, Loves the Limelight, but then Fridge Brilliance kicks in when you find out later on that Kanako's sister, Kanata, is an otaku as well—to be specific, the author of Kuroneko's favorite series Maschera. So while Kanako may find anime and manga hobbies weird, she's ultimately okay with it.