The original Metroid released in the US and Europe is the only game in the series to use passcodes. The original version released in Japan had save slots. However, the western versions did not have these slots, instead utilizing a passcode system for restarting. When the player died in the game, they would be given a code to use. After they entered the code, they would be brought back to the starting elevator of the area they were currently in with all of the upgrades acquired in the preceding play. This was the only way to "save" the game. There are obviously multitudes of codes available in the game; those below are some that start the player in special areas, with more upgrades, or with other interesting results.
It should be noted the system used is a passcode system rather than a password system: rather than specific words being used to achieve specific programmed results, the game parses the text entered on the Password Screen as actual program code and generates a game state from it if it is valid. As a result, all apparently significant phrases (with the exception of the debug code) are coincidences.
Samus will spawn in Brinstar with the Ice Beam with the Wave Beam sprite, all upgrades, armor, infinite Missiles (255) and unlimited energy—however, this invincibility will only last for 3 playthroughs; after the 3rd playthrough, she will start taking damage again. It is believed that the code stands for North American Release Password, that developers put in as a debug code. Despite this the code is not exclusive to the NA version and works on the PAL version as well.
Samus will spawn suited in Tourian with 239 Missiles, all available Energy Tanks, and all upgrades.
Samus will spawn in Tourian with 250 Missiles, all available Energy Tanks, and all upgrades excluding the Wave Beam. This code is for those who want to view the best ending of the game, as this code leads to it easily.
As soon as the code is inputted, the game will direct back to the title screen. This is primarily useful for people that accidentally chose the Continue option when they wished to start a new game.
Samus will spawn suitless in Brinstar with about 200 Missiles, 3 available Energy Tanks, and all upgrades excluding the Long Beam, Morph Ball Bombs, Screw Attack, and Varia Suit. With this code, it is not necessary that Samus defeat Kraid or Ridley; the gateway to Tourian is open.
Samus will spawn suitless (pink leotard, brown hair) in Kraid's Lair with 36 Missiles, 1 Energy Tank, the Wave Beam with no Long Beam, the Screw Attack with no High Jump Boots, and Bombs with no Morph Ball. This will also increase the difficulty level and change the ending.
Samus will spawn suitless in Brinstar with no upgrades, Energy Tanks, or Missiles.
Because it references an invalid starting location and generates a ridiculous game time value of 2861643271, equivalent to 314.5 years, this password has different (albeit undesirable) effects depending on whether a console or emulator is used. Entering the password will either cause the game to be directed back to the title screen like the
333333 KKKKKK password, or it will cause a screen-wide graphical glitch that prevents the screen from scrolling to the left or right, trapping a suitless Samus on the first screen of Brinstar. Entering it can also cause the game to crash at a black screen; this is most common on the Nintendo 3DS Virtual Console version, and the player must hold down the power button for 10 seconds until the console is turned off.  If an SD card is removed when the game has crashed, the player is prompted to press the home button to return to the HOME Menu. Entering the password on the NES Classic Edition console will display a "C7: An error has occurred" message and send the user back to the main menu. Similarly, inputting the password on the Nintendo Entertainment System Online service on Nintendo Switch simply states that "An error has occured within the game," prompting the user to return to the game selection menu. Amusingly, the game state this code generates does result in Ridley having been defeated.
A playable version of the Engage Ridley password. Tourian, suitless, with Varia, 82 missiles, 3 Energy tanks, no Morph Ball, just like with the Mother Brain password, You've only got the Ice Beam on your hands, so you have to play this carefully. It's your only choice to tackle Mother Brain, since you need the Morph Ball to backtrack in a normal playthrough. If you want the Morph Ball, you could use the second controller glitch to warp Samus back to Brinstar.
Samus will spawn suitless in Ridley's Lair with 255 missiles, 6 Energy Tanks, and all items. All doors, except for the boss door to Ridley's room, are opened. Kraid's Statue is shot, and Kraid and Mother Brain are defeated.
DRAGON BALL Z
Dragon Ball z
Samus will spawn suitless in Norfair with 172 missiles, 5 Energy Tanks with only 30 units of energy, Screw Attack, High Jump Boots, Morphball and Bombs, and the Ice Beam along with the Long Beam. It is not necessary that Samus defeat Kraid or Ridley; the gateway to Tourian is open. The background music will be gone after Samus leaves Norfair, unless she gets a Power-up. Also the Varia Suit will not be on its respective statue, neither Samus will have it in her arsenal.
Samus spawns suitless in Tourian with 156 missiles, 5 energy tanks, the Ice Beam, and all other powerups except for the Long Beam and Morph Ball. Mother Brain is already defeated.
Samus will spawn in Brinstar, with two Energy Tanks and Missiles. No powerups, though.
Samus spawns in Norfair. However, she does not have varia.
- ^ DA Boredman (2009-01-26). The Best Metroid Password. Retrieved on 2014-04-22.
- ^ McWhertor, Michael (2011-08-31). Under No Circumstances Should You Use This Dirty Password on Metroid for Nintendo 3DS. Kotaku. Retrieved on 2013-03-16.
- ^ Flathead Sam (2016-12-04). Engage Ridley on the Mini NES. Retrieved on 2016-12-29.