The Koopalings were originally going to be a part of the game, but were removed for unknown reasons. Sprites for of all seven of them have been found, with Roy's shell being miscolored as green instead of pink.

There are several test levels left in the game's ROM. In one of them, Iggy Koopa is actually the boss, but due to him having no coding, he dies as soon as you enter his screen.

The enemy "Starfish" is a reference to Starfy of the Legendary Starfy series. The enemy bio states that he is rumored to be a prince of a kingdom, which Starfy is, and all of the Starfish's sprites are Starfy's with sunglasses added on.

There is an unused icon of a stack of papers stored in the game's memory.

Within the game's data are sprites for Glad and Calm Goombas; the final game only features regular, Mad, and Sad varieties. Of note is that the Calm Goombas' sprites depict them with a pastel green palette, whereas the final game only differentiates Calm enemies from regular ones by having them stay asleep until provoked. Both unused Goomba types also feature a considerably different art style compared to the final game, indicating that the removal of color coordination for the Calm vibe occurred at around the same time as the overhaul in the game's aesthetics.