Yesterday's tool-assisted speedrun (TAS) block at Summer Games Done Quick ended with a Super Mario Bros. 3 run that lasted barely longer than a blink.
The ridiculously rapid run is the result of a newfound glitch discovered by TAS speddrunner ais523, which basically involves pressing buttons at an extremely fast rate -- some 6,000 times a second. Ais523 explained the glitch on Reddit following the run.
...if you're reading the controller repeatedly until you get two values the same (in order to work around the DPCM/controller conflict), then if the controller reads a different output each time (because you're mashing the controller really fast), it's going to get stuck in a loop, potentially allowing for the code that handles the start of a frame running recursively. If the game isn't designed to expect that to happen (and if the code in question isn't really laggy, why would it?), bad things happen, and it was a case of finding a game in which the bad things in question would happen to let us win instantly.
Aided by total_, ais523 got the glitch working with Super Mario Bros. 3. The run was performed by TASBot, the Nintendo R.O.B. robot modified by marathon regular dwangoAC to run controller instructions.The game began, the game ended, and people cheered, as seen in the YouTube video posted by Countryclubguy.
You can catch more of the Summer Games Done Quick TAS block over at the event's Twitch archive.