Entering the cheat code "UGLYMUGS" and viewing the game's credits will display a group photo of the game's developers, Left Field Productions.
Contributed by MehDeletingLater
The game's memory contains unused graphics of some kind of debug font.
Contributed by MeleeWaluigi
Hidden within the rom is an unused string of text that is repeated many times:

Please don't copy this game... that would be rude. Hey!
What are you doing looking at this binary when you should be
looking after my shed?
Contributed by DeerBoarDude