They need to hook up with retired military and get some help with the AI. In Crysis 2, the enemy troops walk in single file, clustered, and all the enemies are just plain dumb as hell. If they give you a rifle with a scope, then the weapon fire should alert the enemy, especially if you just shot him...lol... unfortunately, if you are too far away, you can take shot after shot while the enemy AI just stands there and takes it. If you include long range weapons like a sniper rifle, then by all means program the damned AI to react to it... otherwise, leave them out... but you know you can't do that.