Ankoku Marimokan - Sneak in Destroy Final (eng) - Adult Sex Game

Renka, the heiress to her family's dark business, is approached with a risky request:
break into the headquarters of a criminal organization and steal a top secret disk from the bottom floor.
She'll be surrounded by heinous villains disguised as a guard.
Renka says "no problem", grabs her sword, and takes the mission.