Captures the niche market well, I've never played another game quite like it. But peevish controls and AI let it down.
The game has a good tutorial system that goes through all the basic skills that you need to complete the missions effectively. You aren't just limited to running around with a gun. You can drive a variety of vehicles and aircraft, jump out of aero planes, command troops and much more. The campaign is a series of missions in which you must complete a series of assigned tasks. Most of them are reasonably straight forward, go here, kill the enemies, extract hostages, make the area safe, etc. But some of them require some quick thinking (or a quick google for a walkthrough). There is a certain amount of player input in the progression of the campaign. Sometimes you can choose to accept a task or not, but mostly the story line is pretty linear and your decisions don't matter all that much overall.
The graphics in the game are great. The models are very detailed and the environment looks fantastic. Having been to rural areas of the middle east myself I think it's been done pretty well. There are villagers walking around looking after their sheep, there are birds circling overhead, the terrain is desolate and rocky. There was one mission where I was injured and retreating under fire, and a rabbit ran out right in front of me and off into the distance. Thought that was fantastic. There could certainly be a bit more "life" put into the human models, especially the villagers, but I don't think that's really very important. There are other areas of this game that really do need some urgent attention.
The controls in this game are horrendous. Due to the variety of actions you need to perform in this game the amount of controls you have to remember is pretty ridiculous. They aren't intuitive at all, you simply have to play enough to remember them. Assigning teams and giving orders to your team can be an infuriating and tedious task.
The AI of both friends and foes can be completely awful. Enemies are slow to react. The way they normally end up killing you is simply from being hard to spot and sniping you from long range, rather than actually having any intelligence. Your comrades can be thoroughly stupid. I've found that on foot, they are usually not too bad. Unless you specify otherwise they simply copy what you do. They can spot enemies that are hard for you to see and do at least have the initiative to shoot before the enemy does. However, as soon as they get into a vehicle (getting them in there is hard enough), any brain cells that they did have spontaneously combust. I have to constantly check behind while driving to make sure that the other are keeping up. It can be very frustrating watching your comrades trying to do a simple u-turn. The fact that you might have a grenade launcher in your hands whilst witnessing the stupidity of your team mates is likely going to be the cause of a lot of self-inflicted failed missions.
The sounds are OK. The voice acting is average, the environmental sounds are adequet but nothing special. Can't help feeling that the noise from guns, aircraft, etc, isn't anywhere near loud enough compared to everything else. There are times when fighter jets pass pretty close by you and you can hardly hear it, now that's not right. I find it a bit strange that this game has a sound track, but I tend to turn the music off as it's more realistic.
So Arma 2 seems to be pretty unique in its genre, in that it at least attempts to cover so many aspects of soldering so realisticly. It succeeds to a certain extent but where it really falls down is in the AI and the controls. There must be a way to make the controls more manageable and it would be nice if your comrades at least had the intelligence to follow your orders accurately and drive properly. For me this is a very immersive game that gives the best insight into soldering of any game to date. It's still accessible for a casual gamer, but you will definitely need to play through the tutorial.