The second boss of the game, Ridley, was named in honor of Ridley Scott, the director of Alien: Das unheimliche Wesen aus einer fremden Welt (1979), as the story and atmosphere of Metoroido (1986) were heavily inspired by this famous science-fiction movie.
Some gamers stumbled upon a glitch in the game, where it was possible to jump through a door and get stuck in a wall. From there, it would be possible to jump through walls into normally inaccessible areas with strange layouts. This gave rise to a popular video legend of the "Secret Worlds" in Metroid, which were only accessible to clever players.
Years later, it was revealed that these secret levels were actually map data belonging to other areas in the game (such as moving from Norfair to Brinstar). The reason for this is is because each room in the game is assigned a number. For example, a room with a code of 05 in Norfair might be a vertical shaft with a door, but in Brinstar, a 05 is a horizontal hallway.
The elevators are what tell the game to change room data and what tiles to use. So, when a player skips the elevator by moving through the walls, they are going to see Brinstar's rooms using Norfair's settings.
As such, there are no secret areas in Metroid. Just incorrectly rendered map data.
Years later, it was revealed that these secret levels were actually map data belonging to other areas in the game (such as moving from Norfair to Brinstar). The reason for this is is because each room in the game is assigned a number. For example, a room with a code of 05 in Norfair might be a vertical shaft with a door, but in Brinstar, a 05 is a horizontal hallway.
The elevators are what tell the game to change room data and what tiles to use. So, when a player skips the elevator by moving through the walls, they are going to see Brinstar's rooms using Norfair's settings.
As such, there are no secret areas in Metroid. Just incorrectly rendered map data.
The events of this game have since been retconned by the Game Boy Advance remake, Metroid: Zero Mission (2004). That game is narrated by Samus Aran as the 'true account' of what happened on her first mission, which includes an ambush of Space Pirates, and additional exploration of the Chozo surface ruins and the Space Pirate ship.
The creation of Samus Aran was inspired by the Ellen Ripley character from the Alien movie franchise. Ridley, one of the bosses from the game, was even named after the director of the first Alien film, Ridley Scott.
The Morph Ball was partly invented out of convenience. At the time, there was only limited memory space for the game's programming, so animating a ball rolling through narrow passages required much less data than a computer figure crawling on all fours; as a nod to this, Samus can finally crawl through narrow passages in the remake Metroid: Zero Mission (2004). The Ice Beam was invented for similar reasons: it only required a different color for the beam and for the objects it hits. It required only a little amount of memory, but greatly expanded the gameplay because the Ice Beam could change frozen objects into stepping stones, which is needed to explore higher areas on the map.