As perfect as a game can get
Portal, though short at 5 hours, represents the best that gaming can achieve. I do not make this claim lightly, as I believe Portal holds the spot with no more than a half-dozen other games as representative of the medium's best offerings.
I'm sure others can write summaries on the plot and mechanics of the game itself, but what makes Portal successful beyond measure is the integration of storytelling mechanics into the gameplay mechanics. Few games are successful in this manner, and even those that can pull it off (Ico and Bioshock come to mind), none add wit and satire (nor do they even attempt to).
This integration and elevation of storytelling represents the future of gaming. It's not a cudgel to be wielded by a narcissistic game designer who intends to force upon you his or her story at all costs, it's the subtle and invasive storytelling mechanic employed by the best in Hollywood. Portal is designed as a game and it never forgets its heritage. By not trying to be a movie or a visual novel, it breaks new ground in welding story and gameplay.
