Zillion, known as Akai Koudan Zillion in Japan, is a space adventure platform video game designed for the Sega Master System as a companion for the Zillion anime in 1987. The game is a free-scrolling platform/adventure in the vein of Metroid. It also has objects to be inspected and the necessity of enable things by accessing codes in vein of Impossible Mission. A sequel to the game, Zillion II: The Triformation was also released.
Zillion prominently features Sega's egg-shaped mascot, Opa-opa, who stars in the Fantasy Zone games, also available for the Sega Master System.
Source: Wikipedia, "http://en.wikipedia.org/wiki/Zillion_%28video_game%29," available under the CC-BY-SA License.