Oreimo (which is known as Ore no Imoto ga Konna ni Kawaii Wake ga Nai in Japan) is an anime based on a light novel series written by Tsukasa Fushimi and illustrated by Hiro Kanzaki.

Kyosuke Kosaka is a regular 17-year-old high school student, and his younger sister Kirino is a 14-year-old middle school student. The two siblings haven't had much of a relationship in years, due to Kirino basically igoring Kyosuke. It also doesn't help that Kirino is pretty and smart, while Kyosuke is simply average. However, something happens that causes the siblings to start talking to one another again.

One day, Kyosuke and Kirino accidentally bump into each other, causing Kirino's bag to fly. After Kirino quickly picks up her things and bats Kyosuke away, she makes a hasty retreat out of the house. After she leaves, Kyosuke notices a DVD case that had fallen under some furniture in the entryway. The case is for a magical girl anime series, but inside the case is a disc for an adult game that focuses on little sisters.

Through some deduction, Kyosuke comes to discover that the DVD and game belong to his little sister, which surprises him. One night, Kirino takes Kyosuke to her room and admits that she's an otaku with an extensive collection of not only moe anime, but younger sister-themed adult games. Kyosuke promises to keep the collection a secret from their parents. By the end of the first episode, Kirino is trying to include Kyosuke in her hobby, much to his chagrin.

I have to admit that at first, I thought Kirino's interest in the younger sister-themed adult games was a little odd, but by the end of the first episode, it's made clear that in some respects, she is a little naive about her interest. Also, it's made clear that Kirino is more interested in the cuteness of the little sisters than in the other aspects involved in these games. By the end of the first episode, I also saw that Oreimo has the potential to have some interesting things to explore in regards to relationships between siblings.

Oreimo has a very "cute" look to it, especially in the character design for Kirino. However, due to the fact that adult games play a pivotal role in this series, it's not one I would recommend to younger viewers; however, I will stress that in the first episode, there are only a couple of shots shown of a game, and what is shown from the game is very innocent. But even with that, I still would hesitate to recommend this series for younger viewers.

Personally, I would recommend Oreimo to anime viewers who are 15 or 16 years of age and older.

Title	Episodes	Release Year(s)	Director	Studio	N.A. Licensor
Oreimo	12	2010	Hiroyuki Kanbe	AIC Build	Aniplex of America
Oreimo	4	2011	Hiroyuki Kanbe	AIC Build	N/A
Ore no Imoto Konna ni Kawaii Wake ga Nai	13	2013	Hiroyuki Kanbe	A-1 Pictures	Aniplex of America