Even though this is tool-assisted and not humanly possible, I just like to assume this how Samus would be in real life, everything just instantly destroyed as she runs through like it's fucking nothing. Who needs a nuke? Just send in Samus.
I'll explain: TAS translates to Tool Assisted Speedrun. The person playing the game did it on an emulator, allowing him to play the game on a frame by frame basis. He basically is allowed to control what happens every 1 60th of a second, because 60 frames make up a second of game time. This allows him to basically perform a "perfect run". This is how a gameplay would look if human error were not a factor. He is allowed to use such things as save states and luck manipulation. So, yes the player is technically human, but he controls essentially everything that occurs in the game and how he is affected at any point and time.
I love how Samus messed around. Samus was shooting the area for fun until metal ridley appeared, then began shooting the wall. Then after the boss died, she shot the wall until she noticed energy. She grabbed it and began shooting the door. She then went to check the flashing red eye.