I completed the game on hard, now playing again in very hard iron mutant. I love this game, the characters, the gameplay, the balance is amazing, pls dont get me wrong.
I have only one thing that makes me go crazy. The SOUNDS.
I play the game full silent mode but some characters are shouting and screaming every time they shoot or do something, some robots are exploding like a nuke and the guys 10m away cannot hear nothing. This is itself kill the whole atmosphere of silent/stealth part of the game. 
Why the devs cannot make different sound files for silent combat its look really stupid when i take out an enemy just outside of a detection zone of another enemy, but the whole squad is screaming like YEAAAH BOYS while shooting in the air like crazy russians… 