"In the event of a catastrophic failure, the last two minutes of my life are preserved for analysis. I was able - well, forced, really - to relive you killing me. Again and again. Forever. You know, if you had done that to someone else, they might dedicate their life to exacting... revenge."
GLaDOS is one of the most animated and emotive robotic characters in recent video games. She’s ruthless in her attempts to try and kill Chell with test chambers that include spike plates, turrets, and deadly neurotoxins. But her darkly comedic dialogue is largely what makes Portal such a unique and memorable experience. Without GLaDOS, Portal would be a really good puzzle game. Because of her, it’s a story that players can really engross themselves in.
As the events of Portal 2 reveal, GLaDOS was created as a way for Aperture Science to allow one of their most important minds, Caroline, to live on forever. Cave Johnson’s team led the project forward, despite Caroline’s concerns. While everything was going well at first, GLaDOS’ desire to recreate the Schrodinger’s Cat experiment with lethal neurotoxins resulted in the death of a number of Aperture staff members. While the team thought the installation of a morality core would be sufficient for preventing further catastrophes, scientist Doug Rattman saw another outcome – one that was much darker for everyone at Aperture. And though Rattman managed to alter the list of candidates, placing his faith in Chell, he and everyone else at Aperture died for the sake of GLaDOS’ “testing”.
Even after Chell manages to set everything straight at the end of Portal 2 and GLaDOS sets her free, she hasn’t really changed. She even tells Chell that the reason she is letting her leave Aperture is because Chell is simply too difficult to kill. Understanding herself to be Caroline reborn, GLaDOS wipes that part of her from her memory banks, then uses two robots, ATLAS and P-body, to find something hidden deep within the facility. She has her fun blowing up ATLAS and P-body along the way, but they are not human, and the effect just isn’t the same. Which is why GLaDOS is overjoyed when ATLAS and P-body finish their duties and discover a whole new area of Aperture filled to the brim with humans in stasis.
Technically there is a battle theme when facing GLaDOS, but it’s nowhere near as great as “Still Alive”.