The 4th Unit 2 is a direct sequel to The 4th Unit. The young and pretty bionic soldier Blon-Win has exposed the dark schemes of the trade organization WWWF. However, a new conspiracy is rising. WWWF has employed another bionic soldier, a young woman named Dalzy, who manages to seal Blon-Win's psychic powers. Blon-Win is arrested by WWWF and must find a way to contact her friends, escape, and defeat the treacherous organization.
The sequel follows the same gameplay format, being a predominantly puzzle-less Japanese-style adventure with an interface that combines menu-based verb selection and interaction with objects and characters highlighted on-screen. Compared to the previous games, the gameplay is more streamlined and the menu contains less commands. Rarely used options such as answering "Yes" or "No" during dialogues or the command "Rescue" have been eliminated.