Using the regular system39.exe works fine and the text during the intro is readable.
I also tested Rance IV and there the intro text looks normal with xsystem35.
Edit: I just tried Rance III (without the III+ fan patch) and I see the same issue with xsystem35.
Environment
Clean Rance III+ installation (I followed the wiki https://alicesoft.fandom.com/wiki/User_blog:SupremeJUMBO/Rance_III%2B)
Using the regular system39.exe works fine and the text during the intro is readable. I also tested Rance IV and there the intro text looks normal with xsystem35.
Edit: I just tried Rance III (without the III+ fan patch) and I see the same issue with xsystem35.