Arma II: Operation Arrowhead
Arma II: Operation Arrowhead plays very much like it's predecessors. The simulation covers Infantry, Armor, and flying fairly well with a high level of realism. This is not like Call of Duty, one well placed shot and you're history, and also one bad decision can get your whole squad killed very quickly.
This time around, the game is a little forgiving when it comes to saves, which are handled by either manually saving or just allow the computer to do it. The game has a neat autosave feature that saves automatically before any heavy contact of the enemy. This is a lot better as the earlier games were so very unforgiving.
Don't take that as the game is easy. You will still draw a lot of heat from the enemy for giving your position away, and if you decide to take the lower ground you and your squad will be picked apart. The most challenging aspect of the game is Infantry warfare. A lot of work has been done to the AI and now skirmishes feel more fluid, there is nothing more satisfying than setting up an ambush and striking at the right time.
When you play the Armor missions, they have that set-piece type of feel, though it's a totally open world. Personally I see using Abrams Tanks as cheating, as even though I played many missions with it, I cannot recall actually being killed in one.
The game makes great usage of the many types of Humvees and also Bradley Fighting Vehicles. Unlike the Abrams, these light armored vehicles are prone to breakdown and damage. They offer little in long term protection as ammo stores are lower and it just seems like these vehicles get blasted often.
No game is perfect, and the weak link is definitely the Air portion of the game. It simulates Helicopters fairly well, but the simulation of jet aircraft, and the A-10 is lacking. It's like playing a very short flight sim that has some promise. The controls are jerky and it seems like you never actually have full control over the jets. When it comes to the Helicopters, controls are just right and it's very easy fly.
Arma II: Operation Arrowhead is a solid game on it's own, however it has extended it's life cycle due to the support of the modding community. There are thousands of different mods and campaigns to keep you busy for a very long time. For that reason alone the game actually pays for itself in the long run.