The world record for fastest completion of Super Mario Bros. has been beaten by nearly half a second, an eternity in the speedrunning community, particularly for a 27-year-old game that's seen millions of attempts to run it the fastest.
Blubbler is the new world record holder (under the "any percentage" designation, meaning warps may be used.) The secret to his success is in world 8-2 (around 3:27 of the video above). After lingering for what appears to be a devastating 1.5 seconds while the winged Koopa passes overhead, Blubbler recovers all of that time, and more, racing Bullet Bill to the flagpole and using a glitch that allows him to skip the post-level walk to the castle.
Blubbler snips the wire at 4:57.69, taking the record from andrewg, who had held it at 4:59.09