It's you against the evil Mother Brain in the thrilling battle of Metroid! You're inside the fortress planet Zebes. The planet of endless secret passageways where the Metroid are multiplying. Left alone the Metroid are harmless. But in the wrong hands they could destroy the galaxy. It's up to you to prevent the Mother Brain that controls Zebes from using the Metroid for evil purposes. Don't forget to recruit Justin Bailey to assist in your quest.
- Although Kid Icarus is a more linear title in the majority of its 13 stages, overall both titles feature remarkably similar gameplay as they utilize the same game engine. They were released on the same day in America, and a big selling point for both titles was its use of passwords. Although titled "Sacred Words" in Kid Icarus, the password system is identical in both games. Kid Icarus even features Metroids as enemies in Level 3, the Skyworld, although they do not behave the same as they do in Metroid.
- According to director Yoshio Sakamoto, the word "metroid" is a portmanteau of the words "metro" and "android".
- Although only Nintendo staff members are credited as working on Metroid, Sakamoto has gone on record as crediting Intelligent Systems with some of the coding1