In an early version of the game, Peach's Castle lacked the sign, the bridge, and the sliding stone blocks.

One of Peach's Castle's hazards is a bumper, which is mostly used as an item. Coincidentally, this is the first stage to use an item as a hazard, and have a hazard outside of its own universe; Peach's Castle is from Mario and the Bumper is from Super Smash Bros.

After the Super Smash Bros. release in Japan, Nintendo began a poll to gauge public interests for future roster additions. Of the top ten, seven have since been added, with the remaining three left out. James Bond was most likely left out due to legal reasons, as he is not originally a video game character and belongs to a more strict estate. While not playable, Mew and Toad both make cameos with Mew being a rare Pokeball result and Toad being used in one of Peach's attacks in later games.

Ness' victory theme in the first two Super Smash Bros. games is an orchestrated segment of the Eight Melodies song from EarthBound.