Dan Trachtenberg is a commercials director, known for his 30-second spots for Lexus and Nike. I guess he's also a big fan of Valve's Portal video game because this guy's directed a short fan film, with high production values, that can serve as a prequel to the first Portal game.
Trachtenberg uploaded the six-minute video onto his YouTube channel today with no explanation as to why he made the short. Is he trying to attract the attention of Valve and put himself in the running to direct a big budget Portal movie? Is he just a big gamer at heart and wanted to try and show the world what a live-action Chell would look like running around with an Aperture Science portal gun? Who knows, but that won't stop me from enjoying his video.