I've been playing it on hardened and the AI is okay. Sometimes there is a glitch where they stand there until I blow thier head off. My main problem is sometimes they make it a little too hard. By this I mean, I was playing a level where your supposed to clear the mortar pits and they give you a flame thrower. After that there is a tunnel where two Japanese machine-gunners are behind sand pits. As I go out to take them out, they can shoot my arm before my ironsights can be moved onto them, making me aim all over the place, then they throw a couple hundred grenades, so I throw them back, unless of course I can't but then I get blocked my my allies and I die. But by then another japanese soldier replaces him. Took me a couple tries but was a little frustrating.