A programming loophole in the Super NES platformer Super Mario World has given speedrunners the ability to build and execute arbitrary code during gameplay, leading to the creation of fully playable minigames built on top of existing cartridge assets.

An in-game hack takes advantage of a convoluted glitch that was previously exploited in order to finish the game in an impossibly quick span of time using software emulators. Starting at the 1:40 mark in the video above, the hack is deployed, and new code is written using an array of eight emulated Super NES controllers -- no keyboard input or explicit programming language is used to create these new minigames.

The discovery follows up on a similar hack for Pokemon Yellow that allows players to overwrite the game's code using only the Game Boy's controller input. Fans have since used tool-assisted speedrun tech in order to produce in-game art and other unexpected results.

If the videos above left you confused and maybe even a little frightened, that's normal; the Super Mario World hack made its debut during last week's Awesome Games Done Quick charity marathon to a crowd of stunned onlookers. Have speedrunners gone too far this time? Is there anything we can do to stop them?

This article was originally published on Joystiq.

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