Yea, it makes it difficult, but helps you become better with different weapons, if you consider campaign good at helping you get better (which I do).
Umm kinda but not really.... I think by the end of campaign I will be a beast a sticking though lolz...
It really is not that hard. I played on heroic (Legendary is fun, yes, but anoying when grunts like the sticky grenade a bit to much). I don't remember skull names, but here is what they do: Promotions for everyone No radar Less ammo Catch Another one. I die like 3-4 times a level. Make it with like 10 000 points to spare.
The easiest way is to play on narmal with some skulls activated including Mythic, Thunderstorm, Cowbell(silver doesnt count as multiplies but who cares?), Grunt B-day(HURRAY!!!), tough luck, and tilt. then without to much of a hassle, you'll have all the scoring done.
Here are some tips on Campaign points: -Play on Heroic difficulty. -Activate 6 or so skulls, but not blind, or any of the really hard ones. -Play with a friend who already has all the points already. -Use the BR and carbine whenever possible to get easy 1-shot-kills on grunts as a headshot.