Censorship is never the answer, especially for such loving sisters. Remember that censorship of fictional media is a slippery slope and your media are surely may be next~
You can either download the file called hpatch.rpa in this repository, or you can use the bundled installer I set up to make it easier. hpatch.rpa is straight from the delisted original game, but the installer is from me - although it is also fully open source in this repository as well.
Find the patch file here and put it into Game Directory/game/. The game directory can be found by right-clicking the game in your Steam library, hitting Manage, and then Browse Local Files.
Download the installer from the releases page and run it. It only supports Windows and Steam installations of the game. The installer will automatically find the game directory and install the patch for you. The manual installation method is still available if you prefer that or don't have Windows/Steam.
I also decompiled the patch, which can be found at patch.rpy. This is kinda useless, but it's there.. for being there, I guess.
