100g - Saving the world as your girlfriend.
My girlfriend saved us all in XCOM: Enemy Unknown, she was The Special One. Although she didn't land the killing blow on the Uber Ethereal (missed an 88%), our friend Roddy avenged his late wife (lying dead at his feet) with a Plasma Sniper round and whispered "This is for Libby" (or rather I did lol).
I do think though that XCOM's achievements were pretty great overall, it needs more DLC!!
Slingshot was cool and I'm ok for some more mission packs of this size, as long as there is something meatier coming!
And more customization please!! Hats, beards, haircuts, helmets, armour decos and even colours/camos.
Sorry, went a bit off topic, I saved the world as my girlfriend, she was indifferent