Yes it's difficult - and therefore not for lightweights who expect to complete a game in a couple of hours!
Yes, it's difficult. The publishers assume that purchasers have already played through Conflicts 1 & 2 and are therefore expecting a reasonable challenge. This game is hugely atmospheric - whether you are shooting up VC AA guns from a Huey to the sound of 'Going Up the Country' or leading your squad through the rain in poor visibility, it is utterly absorbing.
Unlike previous Conflict games, your fellow soldiers are flawed - they can panic and become unpredictable in battle. I loved this feature; at one point the squad was under mortar fire, pinned down by 2 machine gun nests and with a man down from a mine. Without orders, one guy tosses a phosphorous grenade which rebounds from a rock and sets fire to the whole squad. Excellent!
Don't believe the whingers - this is a difficult game (the aiming is a little unforgiving) but if you want a game that will genuinely challenge you a sopposed to something that you can walk through in a couple of hours, buy this.