Divi-Dead is a Japanese 2D adult game released by C's Ware in 1998.
 The game's theme falls into the category of adult horror, as it deals with supernatural and sexual topics.
 Certain images from the game are brutally violent and strange, while others are lighthearted and erotic.
 It is a visual novel that involves a supernatural mystery which the player solves in order to complete the game.
 The player makes certain decisions throughout the story, which may lead to different endings for the game.
 Along with True Love, Divi-dead is often credited for being one of the games to start the interest in adult games outside Japan.
 An English translation was released by Himeya Soft.
Shuffle!
 (シャッフル!
 , Shaffuru! )
 is a Japanese visual novel developed by Navel.
 It was originally released as an adult game for Microsoft Windows on January 30, 2004.
 It was subsequently followed by an all-ages release for the PlayStation 2 (PS2) and an expanded adult release for Windows.
 The Windows version was localized in English by MangaGamer in 2009.
 The gameplay in "Shuffle!"
 follows a branching plot line which offers pre-determined scenarios and courses of interaction and focuses on the appeal of the female main characters.
 "Shuffle!"
 has been re-made into an expanded version called "Shuffle!
 Essence+".
 It has expanded routes for the original five main heroines as well as new routes for six other characters.
 "Shuffle!"
 also has three spin-off sequels: "Tick!
 Tack!
" , "Really?
 Really!
" and "Shuffle!
 Love Rainbow".
School Days (スクールデイズ , Sukūru Deizu ) is a Japanese visual novel developed by 0verflow, released on April 28, 2005 for Windows as an adult game.
 It was later ported as a DVD game and for the PlayStation 2 (PS2) and PlayStation Portable (PSP).
 The story, a dramatic slice-of-life, follows Makoto Ito, a high school student who becomes the ambivalent love-interest of several girls during his second term, and the effects this has on himself and his relationships with other characters.
 Though the game requires little interaction from users, "School Days" engages the player through a plot that they are given opportunities to change the course of during play.
 The game concludes with an ending specific to the outcome of the story, some of which became notorious for their graphic violence.
WWF Raw (also known as WWE Raw or WWF Raw is War, depending on version) is a video game released on the Microsoft Xbox and Microsoft Windows by THQ in 2002.
 It is based on the television series of the same name.
 It was the first WWE game released on the Xbox and also the last WWE game released on PC until the release of WWE 2K15 thirteen years later in 2015.
 A sequel was released in 2003.
 It is also the last game released under the WWF name, as the World Wrestling Federation changed its name to "World Wrestling Entertainment" in May of that year.
Tayutama: Kiss on my Deity (タユタマ -Kiss on my Deity- ) is a Japanese visual novel developed by Lump of Sugar.
 It was first released as an adult game for Windows PCs on July 11, 2008 in both limited and regular editions, and was later followed by an Xbox 360 version.
 "Tayutama" is Lump of Sugar's third title after their previous titles "Nursery Rhyme" and "Itsuka, Todoku, Ano Sora ni".
 The story centers on the male protagonist Yuri Mito, a high school student who is the son of a family that presides over the local Shinto shrine.
 As Yuri performs a ritual to transfer a relic that hosts a fictional, supernatural race called Tayutai, he and his friends accidentally summon a goddess, who incarnates as a young girl.
Rocket Riot is a downloadable video game developed by Dutch company Codeglue for PC on Steam and Windows 10 the Xbox 360's Xbox Live Arcade service and the marketplace for Windows Phone 7.
 The title is published by THQ and was released on June 17, 2009., on November 11, 2011 the game released on iOS.
 On October 19, 2016 the game released on Steam and Windows 10.
Megachu!
 -Megamisama Chuuihou- (めがちゅ!
 -Megamisama Chuuihou- ) is a Japanese adult game by Front Wing, which was later adapted to a three-episode hentai anime series.
 The story is a spin-off of "Djibril – The Devil Angel".
 The anime was released in North America by Kitty Media as "Oh My Sex Goddess", a title apparently parodying "Oh My Goddess".
Time Leap (タイムリープ , Taimu Rīpu ) is a Japanese visual novel developed by Front Wing.
 It was first released as an adult game for Windows on December 27, 2007, and it was followed by an all-ages version release for the Xbox 360 on June 25, 2009.
 "Time Leap" is Front Wing's thirteenth title, along with previous titles such as "Megachu!
".
 The game is Front Wing's first title to feature 3D computer graphics, as well as utilizes anti-aliasing and HDR rendering technologies.
 The gameplay in "Time Leap" follows a linear plot line which offers pre-determined scenarios and courses of interaction and focuses on the appeal of the five female main characters.
Island Days (アイランドデイズ , Airando Deizu ) is a tower defense visual novel video game developed by Klon in collaboration with 0verflow for the Nintendo 3DS.
 It is a spin-off of 0verflow's "School Days" visual novel series, and was released in Japan on July 3, 2014.
 The opening theme is "Paradise (Past Plus Parallel)" by Kyōko Aihara.
Fate/stay night (Japanese: フェイト/ステイナイト , Hepburn: Feito/Sutei Naito ) is a Japanese visual novel developed by Type-Moon, which was originally released as an adult game for Windows.
 A version of "Fate/stay night" rated for ages 15 and up titled "Fate/stay night Réalta Nua" (Irish for "new stars"), which features the Japanese voice actors from the anime series, was released for the PlayStation 2 and later for download on Windows as a trilogy covering the three main story lines.
 "Réalta Nua" is also ported to the PlayStation Vita.
 On October 28, 2005, Type-Moon released a sequel to "Fate/stay night", titled "Fate/hollow ataraxia".
 Its plot is set half a year after the events of "Fate/stay night".

Question: Island Days is a spin-off of an adult game released for Windows on what date?
Answer: April 28, 2005