A modified version of the game, complete with updated graphics, a smaller overworld, and completely different dungeons was released in 1995 for the Satellaview, the Super Famicom's (Japanese Super Nintendo) Japanese-only satellite-based add-on.
Called BS Zelda (the 'BS' standing for Broadcast Satellaview), several sources from Japan allude to this as being intended as a "third quest", much like the second quest accessed via the secret code.
When the game was 'rebroadcast' in 1996, Nintendo changed the map layout again. This revision apparently had a smaller broadcast audience than before, and is known only as "~map2~". This second map could again be thought of as a "fourth quest". Additionally, Link was replaced by the Satellaview mascots: A boy who wore a backwards baseball cap, and a girl who had red hair.