Originally Posted by littlejay
Do they still count for the achievement? or do they all have to be alive?
edit: I just died and the unlocked hero was still there and that challenge was marked complete. I am still on breakdown 1 but it looks like you have to complete a challenge in one run of any mode and it stay completed. It's gonna be uber grindy but it could be worse
The Father is a massive grind. Pre built buildings don't count towards it. Sniper and Killer are there to make sure I never get the last one
Most of them aren't to bad. Just break down ammo crates for the gun guys. And make sure you save an assault rifle. They are really rare in my game. Also whistle mines don't count for the Grenadier (50 explosive kills)