Island Days is a spin-off of an adult game released for Windows on what date?
Island Days: 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. Island Days:  It is a spin-off of 0verflow's "School Days" visual novel series, and was released in Japan on July 3, 2014. School Days (visual novel): 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.
April 28, 2005