The player takes on the role of a 5th-grade boy who is accidentally warped to a fictional island called Endonesia. The protagonist must communicate with the island's 50 sealed gods in order to return home. The boy does so by obtaining several abilities called Emo powers, which draw on his emotions, and the emotions of those around him. The game features day and night cycles as well as days of the week, with the island stuck in a 10-day time loop
Endonesia was developed by Vanpool, which is composed of former members of Love-de-Lic. The game's instruction manual was made similar to a travel pamphlet. Titled Endonesia Airlines, it includes a map, photographs of food and wildlife from the game, and letter of welcome to the island.