There are a few mistakes in the end credits. Birdo and Ostro had each others name, Hoopster was misspelled Hoopstar and Clawgrip is known as Clawglip. These mistakes were not fixed in the Super Mario All Stars version, but were fixed in Super Mario Advance.

The "Item Get" jingle from The Legend of Zelda is in the game's files. It was possibly used for test purposes.

At the start of World 1-1, the player falls from a door in the sky that is normally impossible to enter. If you hack the game so that there is a platform under the door and enter it, the game will respawn the player back to the start of the fall and remove the platform, forcing you to begin the stage. This also occurs in the Game Boy Advance version of the game.

Super Mario Advance was a launch title for the Game Boy Advance and opens with a short cutscene featuring the playable characters walking and pulling up the game's logo from the ground. The cutscene features them walking in a small lit square, with the rest of the screen being dimmed until the characters are in place to start pulling up the logo, when the borders slowly brighten. The resolution of the bright square is 160x144 pixels, the screen resolution of the original Game Boy and Game Boy Color, with the fade-in meant to demonstrate the increased resolution of the Game Boy Advance.

Found within the game's data is an unused line of the boss Robirdo saying "I'm gonna finish you off!".