One password, discovered over 20 years later, long after the Metroid password system had been completely reverse-engineered, does not grant you all items. This password just crashes and resets the game:

One password, discovered over 20 years later, long after the Metroid password system had been completely reverse-engineered, does not grant you all items. This password just crashes and resets the game: A Profanity-Laced Video Game Password That Breaks Everything | Max Woolf’s BlogMost of these passwords were gibberish that required a pen-and-paper to write down and remember. One password, however, is more memorable, and much more sinister.Max Woolf's BlogMax Woolf
One password, discovered over 20 years later, long after the Metroid password system had been completely reverse-engineered, does not grant you all items. This password just crashes and resets the game: