On the stage selection screen, the icon for this stage has a flat-color background, unlike the stage itself. This is a holdover from the original demo (as seen on the right), where it was a four-platformed stage with the flat-color placeholder background.
Emerald Hill Zone was the first stage programmed by Gregory McLeod as Super Smash Flash began development as a completely different game before becoming a Super Smash Bros. fangame. This explains why it is the only third-party stage in the game.
During the launch of Super Smash Bros. Brawl, many websites that provided information of Super Smash Flash incorrectly called this stage "Green Hill Zone".