I don't necessarily agree with all of these, or even the order of them, but it got me interested in a topic like this.
Also I got 6/10 on that list. Wonder if that says anything about me. In my defense though I did not betray Wrex or Mordin or Legion. To me, those are the most evil choices.
Anyway, point of this topic is to pick a choice, or perhaps compile a list of choices, of the most awful things you can decide to do in a video game. And I mean like the kinda stuff in the video, not just when you run around in Postal killing trout.
I got one to start off with:
Selling Fenris back to his old slave master in Dragon Age II.
Worst I've seen is in The Devil on G-string. At one point Yuki tries to be cupid for the protagonist and her sister Mizuha. You have the option to respond to that by sexually abusing Mizuha which mentally destroys her and has her give up on life. You end up getting killed by her sister in the end. Quite a sick bad end.
Getting to the "evil" ending in Demon's Souls is pretty brutal, where you Spoiler strike down and literally trample over the Maiden in Black who helped you in a lot of ways along your hard journey.