This video may be just more than 50 minutes long, but I managed to have quite a few nostalgic flashbacks to my youth in that short time. I played the hell out of it as a kid. And that was very correct of me, because after all, Super Mario World is the best platformer in the Mario series.
Watching three speedrunners at Summer Games Done Quick 2014 play it at the same time is a treat. If nothing else, you get three times the Super Mario World action. If you're taking a gander at the video, you may want to skip ahead to about 16:20, which is where they actually start.