Story

The Portal games are story driven games, as such the scenario takes an important place in the gaming experience.

In the games you play Chell, a young women stuck in an Aperture Science complex forced by the Artificial Intelligence GLaDOS to solve tests in specialy designed chambers using for solving them the Handheld Portal Device.

Portal
The game has two distinct acts, the test chambers and the escape.

Act 1: The test chambers
The game begins with the player awakening in a Relaxation Vault where they are briefed by an unseen voice, GLaDOS, before being released through a portal. The player is introduced to the testing process and mechanics cumlinating in the procurement of the Handheld Portal Gun. As Chell makes her way through test chambers it becomes clear the facility is devoid of human life and GLaDOS is testing Chell for her own warped definition of 'science'. Hidden dens are found along the way, containing scribblings from an unseen person warning others of GLaDOS. Motivating Chell with the promise of Cake at the end of the testing, Chell is put through tests of increasing complexity. When Chell is no longer of any use to GLaDOS, GLaDOS attempts to kill her by lowering her into a fire. Escaping her fiery fate using the the Handheld Portal Device, Chell makes her way through the facility via maintenance shafts.

Act 2: The escape
Making your way through the facility GLaDOS attempts to lure you back with promise of cake and a party, and claims the attempted murder of the player was a misunderstanding. When she realizes her attempts are in vain she resorts to taunting the player whilst attempting to kill them. Eventually Chell reaches GLaDOS's lair, where she finally comes face to face with the rogue AI. It is revealed GLaDOS murdered everyone in the facility with neurotxin before attempting to do with the same with Chell. Using the Handheld Portal Device Chell defeats GLaDOS by removing her AI cores and depositing them in a nearby Emergency Intelligence Incinerator, resulting in a large explosion that blows a hole in the roof dragging both Chell and GLaDOS upwards. Chell awakes to find herself above ground in the parking lot of the facility, with the burning remains of GLaDOS surrounding her. The March 3, 2010 Patch modified the ending so that Chell is dragged back into the facility by the unseen Party Escort Bot.

Portal: Still Alive
Portal: Still Alive is a Xbox 360 Live Arcade port of Portal, containing additional content in the form of new advanced chambers, inspired by Portal: The Flash version.

Portal 2
Portal 2 was realeased simultaneously on PC & Mac, Xbox 360 and PS3 so the story is the same for each platforme.

Single Player
The narration in Portal 2 is completely differente, it introduces a clear separation in chapters (similar to the chapter in Half-Life), each chapter making the story progress. You still play Chell, equipped with the Portal gun, but the testing isn't a significative part of the story, not as much as in the original game, the story has more depth than simply testing.