In higher difficulties even basic cannon fodder enemies take several shots from high power assault rifles whereas you go down after 3 maybe 4 shots. Disabling the alarm rarely seems to stop reinforcements from coming. Enemies seem to have a hive-mind so if one sees you everyone knows you're exact position even if you kill them before they can do anything. Every time the enemy starts hunting for you, they go directly toward you even if you gave them no reason to. Hit reg is abysmal. Unidad patrols are infinite so if you slightly inconvenience one soldier, they will send the entire army til you die. Your AI squad is hardly even useful as bullet sponges and will sometimes just not revive you so you have to sit there and watch til you die. Ubisoft has yet to properly fix any glitch or imbalance from what I've seen since it's been released. Unless you are insanely patient, this game will give you hypertension, especially late-game if you're a completionist. If you have someone to play co-op with, it's much more tolerable so there's that. But playing solo is actually bad for your mental health.