[South Park: FBW] Should I kill my mom or may dad?

[Navonod]

I've killed both. I haven't seen any difference in game other than a trophy maybe.

 

[Futurdreamz]

Do you have to choose? Can't you do both? :^)

Sadly no. Once you kill one you can no longer interact with the other parent. I ended up killing my dad, I didn't see anything that hints of changes to the story.

Finished the game finally. The last boss battle was incredibly confusing.