I'm finally starting to understand the Mission structure. Replaying the same mission at different difficulty levels causes different things to happen. Sometimes you unlock a skill, sometimes you unlock a collectible and sometimes you get a nice SP bonus.
It was especially surprising to unlock a new skill at the "Easy" level of one of the missions that was not unlocked by clearing "Normal", "Hard" or "Extreme". You pretty much will want to clear the same mission on all 4 difficulties to get all of the available rewards.
It was especially surprising to unlock a new skill at the "Easy" level of one of the missions that was not unlocked by clearing "Normal", "Hard" or "Extreme". You pretty much will want to clear the same mission on all 4 difficulties to get all of the available rewards.