Eroge

An Eroge (エロゲー or エロゲ erogē, is a portmanteau of erotic game: エロチックゲーム erochikku gēmu) 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 nudity or sexual content.

Mostly in the form of visual novels.

Types

 * BL ("Boys Love") Game; A game focused on two males that... uhmm... You know. It does not necessarily have to have erotic content in it, but most of them do. Examples on BL Games, include; Hadaka Shitsuji ("Naked Butler"), Kuro no Tsuki, and all of Nitro+Chirals games.
 * Nukige; Focused on the erotic content, the storyline and characterization (if any) play a secondary role, and only provide setting for the sex-scenes. There does not have to be a story necessarily to the game.

Usually less erotic content

 * Nakige; Games that make you cry your eyes out. These games are meant to have an emotional impact on the people playing it. This category includes games like, Clannad, Little Busters! - All of the games made by Key, go under this category.
 * Otomege; Maiden game. It's a game where the main character is female, and is supposed to get as many guys as possible. This category includes games like; Starry☆Sky, Uta no☆Prince-sama♪, etc. (many of them get an anime after release of the game).