Try changing your locale to Japanese.
To change locale on Windows 7:
1 - Click the "Start" Button.
2 - Click "Control Panel".
3 - Click "Clock, Language, and Region".
4 - Click "Regional and Language Options".
5 - Click the "Administrative Tab".
6 - Click "Change system locale" under "Language for non-Unicode programs (System Locale)
7 - Change actual regional parameters to "Japanese (Japan)" then Restart now.
For Windows 8 and later, you can try googling it.
If that doesn't work... hopefully someone else can help you, or alternatively, wait for the official 18+ version of the game to come out and buy it or buy the all-ages one, or pirate them as I imagine people will upload them, those are likely to work on your regular locale (or at least English-based ones).
Also, next time post in the Grisaia thread directly, please. Good luck!
Edit: Looking again at the pictures, I just have to ask, because I've seen a lot of people do that mistake in the past... Did you actually install the game? By mounting it through
Daemon Tools or something similar? You didn't just unpack the ISO? Don't worry if so, you wouldn't be the first.
