Instead of using an ad agency, Valve has opted to create their Portal 2 commercials themselves.  The developers were able to tweak the spot based on feedback and make changes during production—something not normally possible with an external adency. After viewing the first Portal 2 TV spot, it looks like they made the right choice. It features Atlas and P-body, the co-op play robots, goofing around with the portal gun technology when GLaDOS interrupts them and announces, “we’re going to have fun . . . with SCIENCE.” Have we mentioned that we can't wait for April 19? [via Joystiq]