There is no sign of people anywhere, which makes you wonder "what happened here?". you of course do not trust that voice and continue on through the maintenance shaft, thus emerging into a small observation area designed to look at test subjects, but it is completely empty. she tries to coax you onto laying down, assuring you in it's calm yet afraid voice that it was all just another part of the test and that cake will be served. Guiding test subjects through a maze, but it is a sentient voice, one that you have now frightened. not any more is it just a per-recorded message You begin to hear the voice in an entirely different way. Realizing that there is away out of this, you place one portal on the maintenance platform in front of you and another on the incinerator's wall and jump to But of course not even cake, which you have been promised, is at the end of the platform as it slowly descends into an inferno. even though the idea of "cake" at the end of this all seems off center, even a bit anti-climatic at this point. once the elevator stops, you get off to see the sign "test chamber 19" illuminate, as usual, and glados reminds you once again this is the last test you will take by mentioning cake. you take some time to do the test, come across another one of those dens, this one containing not much more information on what watches you, and you finally arrive at that iconic elevator again, on which she mentions something off beat about "a self esteem fund for girls". For what it was, test chamber 18 was quite uneventful, especially considering it was the second to the last test chamber. But you soon forget about, and make your way out to test chamber 18. This makes you start to question the person whom did it, making you struggle to decide who is right? by the end of the test she instructs you to "euthanize the cube", which is an odd thing to say considering it does not have feelings, hell it isnt even alive.right? Now you start to wonder if that voice, whom or what ever it is, has gone mad just like the person who wrote all those cryptic messages on the wall. they cover faces of people on photos and calenders with writing on the wall suggesting the person whom did this gone crazy. Its just a cube with a heart on it, right? Then you find another den,this one filled with pictures of the goddamn things. By test chamber 17 you get your companion cube and start to wonder the significance of it. these make you question you trust in that voice, because for the first time you have evidence to suggest that the voice over the intercom might not be per-recorded, or even human, but something.else. two of the more common ones are "she is watching you" and "the cake is a lie". packed away behind 2 companion cubes and a faulty hydraulic panel you find a small den filled with tons of trash and even more unsettling.writing on the wall that seems to be written, in blood? though the site seems overall creepy at first glance, you soon read the messages and understand the meaning behind them. this one by far more creepy then all the previous. These lines lead to you getting paranoid, and no amount of glitching and "subject name here's" can make you think differently. on top of that she starts to mention the end of your test more and more often, accompanying vague and unsettling lines such as "you will be missed". the test become more and more dangerous, even coming to the point where they involve military grade turrets. I mean what are the odds it happened before? But then Right? its probably just a per-recorded message for when a test subject knocks over a camera.
of course a machine cannot know what you are doing
You go to put a portal behind a camera she reacts as if she knew, as if she was "watching you". Her voice occasionally glitches out, assuring you once again you are alone in this cold, florescent lit world. Welcomes you to the computer aided enrichment center", so of course you are not being guided by a person.right? Throughout the test chambers At the beginning of the game you would think she was just a voice recording, of course you are assured of this i mean, "She Unlike portal 2, where you knew glados was an ai from the beginning, in portal 1, she was a complete mystery up until the very end. not only did it blend seamlessly with the puzzles, but it gave you subtle hints into what kind of world you are trapped in. One thing portal had over portal 2 was the environment.