While game-breaking exploits allowing arbitrary code execution within Super Mario World have been well-documented in recent months, SethBling was the first player to successfully code a complete game within Nintendo’s classic platformer using only a Super Mario World cartridge, a vintage Super NES console, and a SNES controller for input.
Devoted players have stretched Super Mario World to its limits using PC emulators, and recent discoveries allowed players to reach its credits sequence in record time by effectively crashing the game at a critical point. After becoming the world’s first player to achieve a Super Mario World “credits warp” using original Super NES hardware, SethBling set his sights on an even tougher task: programming an original game on top of Super Mario World‘s codebase in real time — without cheats — using custom processor instructions created by fellow speedrunner p4plus2.
After glitching Super Mario World into a state that allows it to accept user-defined code, SethBling input 331 bytes of custom processor instructions by positioning Mario in pixel-perfect locations and performing specific actions in a precise sequence. The ordeal required almost one hour of precise code input, and a mistake at any point would have nullified the entire process.
Previous experiments with Super Mario World‘s internal code yielded several user-created minigames playable on original Super NES hardware. The process was showcased during many recent speedrun events; emulation technology transformed Super Mario World into Pong and Snake clones at Awesome Games Done Quick 2014, and 2015’s event produced a playable version of the original Super Mario Bros.
Arbitrary code execution within Super Mario World previously required a level of precision reserved for emulators, but recent discoveries altered the game in such a way as to allow users to input code themselves using standard controller input. Currently, SethBling is the only player in the world who has been able to transform Super Mario World into Flappy Bird in real time using original SNES hardware.