Video Game History Foundation founder Frank Cifaldi has released the ROM data for a prototype version of the original Legend of Zelda on the NES, triggering speculation that it could contain significant differences from the final retail version.
Photos of the yellow cart – labelled "NOA COPY 2.23.87" – have been seen online for a whole, but Cifaldi has made its contents public, and people have already begun identifying differences in the code.
A binary comparison between the prototype and version 1.0 of the game – first released in North America in 1987 – shows that sections of the code are indeed different.
Twitter user MrTalida has only been able to play the prototype a few times, but has already spotted that Link exhibits slightly different behaviour when exiting a cave. "Link remains under the ground at his last position for one frame before teleporting to the cave entrance," says MrTalida.
If anything else interesting comes out of the prototype, we'll be sure to update this post.