Because of its scarcity and unique history, King Neptune's Adventure for the NES is considered a collector's item. Color Dreams, a firm notorious for manufacturing unauthorized NES games, launched the game in 1990. King Neptune's Adventure was not extensively disseminated and lacked an official Nintendo stamp of approval. Because of its scarcity and illegal status, the game has become a sought-after item among collectors. However, because to its relatively obscure position and lack of mass recognition, its value is often lower than that of other rare NES titles.