Ah, when I mean achievement I mean the xbox achievements, not bf3 achievements (not sure if bf3 has in-game achievements?). Yeah BO was hard as well, to an extent. I raged a lot of times. Probably forgot about it since it's been about a year already since I finished the campaign. But BF3 is challenging... haha.Oh, on PC I don't think you get anything upon completion. Just the satisfaction of completing the story, like in the good old days
Apparently BO was really hard/cheap on Veteran, basically enables all enemies to have an aim bot.