personally, i love the part right after the final boss (with GLaDOS's quote, "...and frankly, killing you...is hard"), and the end song was great.
i got a kock out ofthe turrets as you're going up the elevator, too
Cave Johnson: "MAKE LIFE TAKE THE LEMONS BACK! IN FACT, I WILL HAVE MY LAB BOYS INVENT COMBUSTABLE LEMONS, SO I CAN BURN YOUR HOUSE DOWN WITH LEMONS!"
GLaDOS:"Burn the house down!"
Made me lol so hard XD. Also the entire part where wheatly is trying to kill you with traps is pretty fun.
Wheatly: Umm... False. Im going to have to go with False, although to be quite honest, I might have heard that one before.
GLaDOS:"I think this is the part where he kills us."
Wheatly:"Alright, this is the part where I kill you!"
Chapter Title:"The part where he kills you"
Ahh, so many good memories. It still doesn't top the cake in portal 1 though. And I was lucky enough not to have the ending spoiled before I finished the game a month ago. Alson, I just finished portal 2 a week ago.
Wheatly: Umm... False. Im going to have to go with False, although to be quite honest, I might have heard that one before.
"You just put him in charge of the facility? He was made by a crack squad of scientists to be a moron, not just any moron, but the dumbest moron ever made."
requirements: when you escape the pit before you get crushed by the spiked platforms, go back when wheatley asks you to. he'll act suprised, and ask you to jump into the pit. do it; get the acheivement; laugh as you hear wheatly's suprise.
also..."so, how are you holding up? because i'm a POTATO."
VERY END spoiler:
you walk out of the vault, allowing your eyes to adjust to the light--then the door slams.
moments later, it reopens, AND OUT COES COMPANION CUBE!!!! IT SURVIVED!!!!