Enter the Minus World! Nintendo Cartridges Share Secrets! by Paul Pollack Secrets in video games are a funny thing. Sometimes they’re gifts from the developers that make you feel like you got somewhere you weren’t supposed to go. Other times… a game winds up in a state it wasn’t built to handle and you actually got somewhere you definitely weren’t supposed to go! Super Mario Bros. for the Nintendo Entertainment System has great examples of both of these kinds of secrets. The Warp Zone is a well-known and beloved portal into later stages of the game. I want to talk to you about another portal, one left completely by accident, that goes somewhere else: The Minus World! The Minus World is a collection of levels composed entirely of arbitrary junk data in memory! In the US players discovered this place through dexterous maneuvering to outsmart the game’s collision detection logic. The results were fascinating but limited. A single level named “ - 1” (as in Minus World!) that repeated in a loop. I want to share with you all another method to enter this place that gives us access to a whole slew of possible levels! This technique was first discovered by some clever Japanese gamers by swapping out cartridges without turning off the console. As I demonstrate this effect we will talk about which hardware components are involved and exactly what they’re doing every step of the way! Paul has a lot of hobbies and interests that move in and out of rotation over time. Sometimes he forgets about one for years and then suddenly remembers he liked doing the thing. Among these are electronics, music, mushroom hunting, and watching the Evil Dead trilogy. Paul writes software to make it easier for people to spend time outdoors for The Wanderlust Group.