You guys are puss puss playing on Crushing. Try playing on Brutal on the original 3 for the remastered version. 2 shots and you're dead. It gives it a very realistic tone to the game to have patience, use the environment to the best of your abilities and to be cautious, almost like in real life.
UC1 remains the hardest of the platinums still. 2 and 3 are a joke. But that Brutal from UC1 in the Airplane Crash, Circle Room and the Blue Room.... well, I still did it... but... *pulls out hair*.
Also, you're doing UC4 Crushing wrong. It's the easiest Crushing of them all. Get Infinite OP weapons and the Slow Motion perk and watch the magic.