Night Slave is an eroge

Eroge

An or Ero-ga is a Japanese video or computer game that features erotic content, usually in the form of anime-style artwork. Eroge originated from galge, but unlike galge, they feature erotic/pornographic content.-History:...

 run & gun role-playing shooter game released in 1996 for the NEC PC-98 computer.

Gameplay

The game's design and gameplay draws inspiration from the Assault Suits series

Assault Suits series

The Assault Suits series is a series of futuristic robotic war video games developed by NCS featuring soldiers manning gigantic humanoid machines dubbed Assault Suits. Spanning the course of 15 years and beyond, the games would be cross-distributed, cross-published and developed between the U.S....

, particularly Assault Suits Valken (1992), as well as the Gradius

Gradius

The Gradius games, first introduced in 1985, make up a series of scrolling shooter video games published by Konami for a variety of portable, console and arcade platforms. In many games in the series, the player controls a ship known as the Vic Viper...

series. It also employs many action role-playing game

Action role-playing game

Action role-playing games form a loosely defined sub-genre of role-playing video games that incorporate elements of action or action-adventure games, emphasizing real-time action where the player has direct control over characters, instead of turn-based or menu-based combat...

 elements such as permanently levelling up the mecha

Mecha

A mech , is a science fiction term for a large walking bipedal tank or robot, including ones on treads and animal shapes.-Characteristics:...

 and various weapons using power-orbs obtained from defeating enemies as well as storyline cut scenes, which occasionally contain lesbian

Lesbian

Lesbian is a term most widely used in the English language to describe sexual and romantic desire between females. The word may be used as a noun, to refer to women who identify themselves or who are characterized by others as having the primary attribute of female homosexuality, or as an...

 adult content

Adult video game

An adult video game is a video game which has significant sexual content , and are therefore intended for an adult audience. Adult games can fall into many genres and have diverse gameplay.-PC and console:...

. The game's armaments system also employs recoil physics

Game physics

Computer animation physics or game physics involves the introduction of the laws of physics into a simulation or game engine, particularly in 3D computer graphics, for the purpose of making the effects appear more real to the observer...

, while the gameplay is varied, including environments such as rainy jungles, snowy wastes, and alien bases.