The problem here is that gamers are so used to being held hostage by z-grade adolescent power fantasies ravelled together by z-grade game designers ('writers') still hacking and hamming away at the methods of film, failing to realise that a new medium requires new standards, new methods of delivery, and generally a new approach that when something daring and interesting (and yes, simple, but most of the very best stories are) comes along they scratch their heads and wonder where the ponderous ten minute cutscenes are. The likes of Kojima have basically inflicted Stockholm Syndrome on a generation.
So no, Portal doesn't have 'formal (read: traditional, familiar) storytelling', omnipresent voice that tells you things throughout the game not withstanding. Rather it has new methods of storytelling which include the player's interaction with a detailed 3D environment and the ludic discovery of plot and character (most notably GLaDOS's). I mean you could argue (Ken Levine does) that this is just a new appropriation of mise-en-scène, but that doesn't ring true with me, because no one gets to actually wander around the stage of a play or the shot of a film poking in corners at their own discretion, directing their interest and attention. We do in games. That's new. That's exciting. Don't dismiss it because it's unfamiliar.
