If you name Link "Zelda" in the nes game you got the alternate quest but I think this joke is eluding to the common confusion among non-gamers that zelda is he main character.
In the original it gave you access to the masterquest version without having to beat the game. There have been a few others games with bonuses for naming the file Zelda as well.
well lets be honest though, link is always a pain in the butt to get high enough level, so to speak, and strong enough to fight the final boss. And normally zelda has some awesome power she's never really learned to use that could twart the evil villian, and apparently in one she even plays some freaking awesome ninja! ...i wanna play zelda >_>