A 40-Year-Old Breakthrough
Forty years after launch, Super Mario Bros. just surprised its most dedicated players. The speedrunning community has confirmed arbitrary code execution in the original NES classic, a feat many assumed was out of reach. On Tuesday, veteran runner Kosmic posted a YouTube breakdown of the new glitch, calling it a major step for future experiments—even if it won’t topple records right away.
Arbitrary code execution, or ACE, lets players feed custom instructions into a game using only controller inputs and in-game actions. Other franchises have used similar exploits to skip huge chunks of content—think The Legend of Zelda: The Wind Waker, various Final Fantasy entries, and numerous Pokémon titles. Mario games have seen ACE before, but the first game in the series had resisted it until now.
How It Happened
The spark came from an unexpected place. According to Kosmic, the team first suspected something new when Twitter/X user @TheLuigiSidekick crashed The Lost Levels on Nintendo Switch Online during a routine playthrough. That footage set off a wave of testing. Runners dug into memory behavior, tried to reproduce the conditions, and chased a path to the same kind of instability in the original Super Mario Bros.
After trial and error—and plenty of guesswork—the community found a narrow setup that lets players bend the game’s logic. The result is full ACE in SMB1. In practical terms, it means you can make Mario jump straight to the game’s finale. Yes, credits warp in the original NES release is possible without external hardware, patches, or save-file tampering.
“If you want, you can now access not just the Minus World, but any world or level you want,” Kosmic told Polygon. “With no hacks or cheats. It’s a glitch that makes anything possible.” For a game that’s been dissected for decades, that’s a startling sentence.