BS Zelda no Densetsu: Inishie no Sekiban
BS Zelda no Densetsu: Inishie no Sekiban
The music that was streamed from the Satellaview was originally from an album released in Japan called The Legend of Zelda: Sound and Drama.
Contributed by xianc78
Both the male and female mascots have two unused sets of sprites in the ROM's data. One set is similar to Link praying at the Desert Palace in A Link to the Past. The other is them as a bunny.
Contributed by xianc78
If you go into Dai-1-wa, Dai-2-wa, or Dai-3-wa with a complete inventory (using a hacked save or Dai-4-wa save file), you can explore the overworld past the normal week boundaries. The problem is, the areas were only really changed from A Link to the Past as they were needed, resulting in a glitched overworld somewhere between A Link to the Past and Sekiban.

The Hyrule soldier sprite data is gone, but their properties remain, so they appear as glitched enemies. All Dark World warps are missing, while trying to use a water warp will crash the game and entering a cave or other indoor location will likewise cause strange glitches.
Contributed by WhiteSamurott
After collecting everything in the game, two item slots remain empty "“ the Magic Cape and Book of Mudora, while coded into the game and fill these slots when hacked into the player's inventory, cannot be obtained normally.

The Magic Cape works as usual (you become invisible and invincible at the cost of magic power), but the Book of Mudora does nothing; as it fills the last slot in the A-button portion of the status screen, you were likely supposed to find the Book and either use it yourself (as in ALTTP) or give it to Zelda.
Contributed by WhiteSamurott