The NES and SNES versions of Super Mario Bros. 2 contain different insta-kill cheat codes, likely used by the game's developers for debug purposes. The code for the NES version involves pausing the game and holding Up/A/B on a second controller, and then unpausing to lose a life. The code for the SNES version is simpler, where you only need to pause the game, hold L and R, and then press Select to lose a life.

There are a pair of glitches that can be triggered with this code in the NES version. If the code is inputted while riding a Rocket, the health bar will effectively turn invisible by displaying all the heart pips as empty, but the player character will emerge unharmed. If the code is inputted during the transition for walking through a door, the player character will continually fall through the floor and lose their lives until a Game Over is reached.