Due to a programming error, the player has a random chance of accessing debug mode in Super Mario Bros. 3 (specifically the one from the NES version of the game, which is carried over to the Super Mario All-Stars port). The debug mode only activates if a value of 80 is stored at the RAM address 7E0160, which can be manually edited by a devkit.

The NES version initializes the equivalent RAM address to 00 whenever the game is turned on, preventing the player from encountering debug mode during the normal course of play. However, due to an oversight, this does not occur in the SNES version, resulting in Super Mario All-Stars reading whatever value is generated by the console itself. Because this value is randomized during bootup, this means that the game has a small chance of activating debug mode in Super Mario Bros. 3 on a retail unit. While the theoretical probability of this occurring is 1/256, it can vary depending on the console's build and the power grid that it is connected to.