[5] The Zillion series prominently features Sega's egg-shaped mascot, Opa-Opa, who stars in the Fantasy Zone games, which are also available for the Master System.

The White Knights, a peacekeeping force within the Planetary System, are on a mission to destroy the evil Nohza (misspelled as "Norsa" in the North American version) Empire's base on Planet X.

Some of the obstacles of the missions include tripwires, enemy guards, laser turrets and force fields.

Aside from unlocking rooms, the player has also the option to make specific actions, such as turning off barriers, deactivating traps, or even committing suicide, among others.

The game is well known for a variety of "special messages" that can be received if the player inputs certain codes in certain rooms.