In 1/92 interview with the game's producer Shigeru Miyamoto published in the edition of Famicom Tsuushin magazine, he was asked if the SNES version of Zelda be the same as the Super Famicom version. He responded that him and his team thought about making some improvements to the SNES version, including a number of things they could not complete in time for the Super Famicom release. Zelda makes full use of the available 8 MB of ROM space, but they knew they were going to need extra space for the English translation. They initially planned to increase the ROM size by 1 MB to solve this, until the compression routine their programmers wrote actually allowed them to fit everything in the original 8 MB storage. Miyamoto joked that they would save those aforementioned improvements for the next game.
Contributed by ProtoSnake