1.08 (a stable release preceding newer 1.09+ bugfix and content updates).
Overwriting files in an existing Japanese installation of the game with the contents of the archive. File: Battle_Demon_Kirsten_Ver.1.08_eng.rar ...
If you are looking for specific or newer scenes, note that subsequent patches (like 1.06 or 1.09) added additional story elements in locations such as the "Harapania Brothel" and vagrant camps. File: Battle_Demon_Kirsten_Ver.1.08_eng.rar ...