GlaDOS singing during the portal ending credits.
Ok, so she was a crazy AI out to kill you, but how can you not love her when she's so cheerful and obsessed with cake? She's like a cuter and more lovable SHODAN :)
Just some random butchering of the splicers in the theatre on hard difficulty to show off my newfound wrench-fu skills.
Will upload a version where I'm actively seeking them out and killing them rather than just waiting and playing whack-a-mole shortly.