[A prototype for one of the most important video games in history][link], with [a meticulous look at the changes][two] between this prototype and the final release.
[link]: http://forums.lostlevels.org/viewtopic.php?t=2471 “Lost Levels :: View topic – The Legend of Zelda prototype”
[two]: http://tcrf.net/Proto:The_Legend_of_Zelda “Legend of Zelda Prototype on The Cutting Room Floor”