Title: Imouto Ijime
Original title: 妹いじめ
Length: Short (2 - 10 hours)
Year: Japan 2009-12-25, English Patch 2011-07-30
Developer: Noir
Publishers: Noir
Language: English
Voice: Japanese
Translation: Muzukashii Nippongo Wakaranai

Description:
I have a little sister...
She's cute. She's my cute little sister Rin.
Our parents got married and we became a family.
However... Recently I started to feel strange.
Now I feel lust for Rin.
I just see your body or touch it and I got a hard on...
Haaa... Rin... You're so cute Rin...
I think I've reached my limit...

Important:
1. You need to change locale to Japanese.
http://erogedownload.com/faq/changing-to-japanese-locale-on-windows-7/

2. No need to install.

Screenshots: