 Development of Sinistar: Unleashed, originally titled Out of the Void, began in 1997. It was handled by GameFX, a small game developer consisting of former members of Looking Glass Studios. At first, the project had no connection, or gameplay similarities, to the Sinistar franchise. When the studio acquired the rights for the Sinistar franchise that year, it decided to refocus the development of the title to fit into the newly acquired property. It altered the game to introduce similarities to Sinistar, although the graphic structure remained unchanged. During development of the game, AGH noted that the final product was expected to be "a combination of Out of the Void's graphical flash with Sinistar's fast and frenzied action."
