This almost broke our brains at first, but in this tool-assisted run by agwawaf you can see that he's playing (and beating) Super Mario Bros. 1, 2, 3, AND The Lost Levels in under 9 minutes using the same controller. Initially, it seems like it shouldn't be possible but as you watch you find all the clever tricks that make it work. Now, we're not speedrun or TAS experts, so if this is total babyshoes let us know. But for now, HOLY CRAP.
To add to the impressiveness, this is actually his SECOND succesful "quad-run", having beaten his previous time of 10:39.