The famous Legend of Zelda theme music that originated from this game came about at the last moment. Nintendo had planned on using the famous Bolero symphony as theme music, when they realized this composition was still copyrighted and couldn't be used. Composer Koji Kondo came up with his famous theme within one day.
The original, full name of the game is "The Hyrule Fantasy: The Legend of Zelda" (hence it is the name by which the game is officially listed in IMDb). "Hyrule Fantasy" was supposed to be the title of the game series, with "The Legend of Zelda" simply being the subtitle of this particular installment. However, during the translation for the North-American version, the main title was inexplicably dropped, and the game was released outside Japan as simply "The Legend of Zelda". This name was subsequently re-used in the titles of most of the sequels, and has thus unintentionally become the series' title, even though some of the installments don't focus on Zelda or feature her at all.
In the manual of the NES (USA and Europe) and the Famicom (Japan) version of this game, an enemy called Pols Voice is described as a ghost with big ears that hates loud noises. The latter description caused confusion among owners of the NES version, assuming that the flute is the right item to use. In the Famicom version, the game makes use of a built-in microphone of second controller. Screaming right into the microphone causes damage to the Pols Voice and defeats them instantly. This feature is not given in any of the NES versions.
In the test version of the game, the player would start out with a sword. However, this version met with a lot of complaints about the game being too difficult and confusing. Director Shigeru Miyamoto then made the bold move of making the game even more difficult (like having to look for a sword first). His expectation was that this would prompt players to share their experiences with their friends in order to solve their problems, and create some kind of game community. His prediction proved correct, and the Zelda game community is still a thriving one almost 30 years later.
It is likely that the game's currency "rupee" is the result of a mistransliteration of the English word "ruby" into Japanese, in which the game was developed before it was transliterated back again (this time technically correctly) into English. Correctly speaking, the katakana transliteration should have had a dakuten diacritic instead of a handakuten diacritic. This is supported by the fact that the official English manual for the game uses the word "ruby", while the German translation of the game itself also used the word "Rubin", which translates as ruby. Nonetheless, future translators of Zelda games adopted this misspelling as an integral part of the franchise's lore, and it has been preserved in every game since as of Zeruda no densetsu: Kamigami no toraifôsu (1991). Likewise, the German translations continue to use the word "Rubin".
In quest 2 the layout of the first 5 underground dungeons are the letters that spell ZELDA, but the spelling is out of order. They are as follows: Level 1 - E Level 2 - A Level 3 - L (and with a period) Level 4 - D Level 5 - Z. In the first quest, the third dungeon's layout may look like a swastika at first glance, but in actuality, it is a Manji, a symbol of good fortune in Japanese.
To this day, this game is considered the most popular video game with the misconception that the main heroes name is referred to incorrectly. Mistakenly people think the main hero you play as is Zelda. Zelda is infact the princess that the hero Link is out to rescue.