These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Blue Sky
Alternate Character Interpretation: Subverted. This is not the fanfic for an interpretation of GLaDOS as in any way well-meaning or kindly disposed towards Chell. This GLaDOS is a pitiless monster, and the story makes clear that the redeeming qualities she showed in Portal 2 were entirely thanks to Caroline, now deleted. Wheatley is shown in a sympathetic light, but with his many flaws thrown into stark relief.
Caroline as well. It's pointed out that GLaDOS resulted in a psychopathic, homicidal, insane A.I. But they started with Caroline.
Ron the Death Eater: GLaDOS is treated a lot less sympathetically than other fics here - it is mentioned that she spends a lot of time trying to eliminate Caroline from her systems, rejecting any humanity within her.
The Woobie: Wheatley, oh heavens Wheatley. Fresh from 300 years of entropy in Aperture Labs and four years in cripplingly boring orbit, he arrives in Eaden, set to fail at everything he sets his hand to, from making bread to just being a decent person. He's crippled with constant self-doubt and self-loathing, feels terribly out of place among humans, and his backstory reveals that he was just an ordinary, perfectly innocent Aperture Science employee who was abducted, tortured, and then rendered immortal so the scientists could try and save their own skins — and he was programmed to have terrible ideas and never recognize them as such. Profound Woobiedom.
Chell, too, given how massively traumatized she is from the testing facility. Even four years later, she still has violent nightmares, plus it took her months to adapt to something resembling normalcy. Then she gets dragged back There. Twice.