In the first game, Metroid for the NES, Galactic Federation researchers discovered a new form of airborne life on planet ~SR388. They dubbed these dangerous jellyfish-like creatures Metroids and captured a few for later study. Unfortunately, as the crew sped toward ~Galactic Federation Headquarters, space pirates attacked the vessel, stole the Metroids and took them to their home planet, ~Zebes. Soon the Mother Brain created an evil Metroid force. Samus's job was to eliminate the space pirates and destroy the Metroids.

In the sequel, Metroid II: Return of Samus for the Game Boy, Samus was sent to planet ~SR388 to make the Metroids extinct once and for all. Her final battle was against the Metroid Queen.

According to Super Metroid lore, after destroying the queen, Samus discovered a Metroid egg, which she procured and took with her to the ~Space Science Academy on the ~Galactic Federation Space Colony. Here scientists could examine the Metroid larva and understand its special organic structure. Naturally, those pesky Zebesian space pirates and their leader, Ridley, stole the larva and too it back to their rebuilt home planet. Samus promptly received an emergency directive from the Federation, ordering her to follow the pirates and save the hatchling. When she lands on ~Zebes, she finds that she must now take on an entire legion of space pirates as well as a new Metroid force.

The planet ~Zebes is made up of six huge sections: the surface area, which is under a constant deluge of rain, is called ~Crateria; ~Brinstar is a jungle area with a heavy maze of foliage; an underground water world called ~Maridia is full of killer crustaceans and ferocious fish; deep below the surface of the planet lies the unbearably hot ~Norfair; the remains of an astronaut crash comprises the Wrecked Ship; and ~Tourian is the control center for the space pirates and Mother Brain. Throughout the game, you must break down color-coded doorways that were designed to prevent intruders from roaming into restricted areas.

As you run, jump, spin, roll and shoot your way through twisted, threatening passageways of this game, you can fire upon ~Chozo Statues, which will reveal special items that will help you in your mission. You can collect missile tanks, power bombs, a grappling beam (which enables you to swing into certain areas), an x-ray scope (which allows you to see hidden passages) and energy tanks. When you destroy enemy creatures, they sometimes leave behind missiles and energy balls.

At the beginning of Super Metroid, Samus is equipped with a normal beam. You can increase her power by collecting the following enhanced beams: Ice, which freezes enemies for a short time; Wave, which sends out a charge in a wavy pattern; Spazer, which is a three-beam attack; and Plasma, the most powerful beam of all. Two special suits of armor, the ~Varia Suit and the ~Gravity Suit, are available for use. The former suit cuts damage from enemy attacks in half and allows you to explore in high-temperature areas while the latter reduces damage from attacks to one fourth and lets you explore freely in water-filled zones.

Special boot items you can find will help you reach higher places, jump continuously, fly through open areas and run at super high speed while invincible. Superpowers you can acquire for use in turning yourself into a living weapon include: morphing ball, bomb, spring ball and screw attack. The screw attack enables you to somersault into enemies and blast them into oblivion.

In addition to battling space pirates, you must face a barrage of freakish creatures and numerous traps. You'll ward off clawed Geruta, fireball-spitting dragons, cacti needle-launching Cacatac, thorny bullet-firing Evir and any number of other creepy, crawly critters. Also, each level has a boss and mini-boss that you must defeat.