Speedrunning is the sort of skill that requires ridiculous knowledge of a game.
Would-be speedrunners have to discover, learn and memorise every shot, every jump, every glitch and every trick in order to figure out the quickest way to beat a game. And that's the easy part.
Then they actually have to do the run, ideally without making a single error. Sometimes they'll have to time things to within a single frame of animation, other times they'll have to deal with random factors that could mess up everything.
Watching one speedrunner play through a game is impressive enough, then. But watching four at the same time? Insane.
This Super Metroid run was part of the Awesome Games Done Quick speedrun marathon that ran for a week and ended up raising over a million dollars for the Prevent Cancer Foundation.
In it, four Super Metroid players speedrun the game simultaneously to see who finishes first. The game takes over 45 minutes to successfully speedrun so there's plenty of room for error, but these guys know their stuff so well that the ending is fantastically close.