Infantry combat is primarily improved by better movement physics and the addition of iron sights. Iron sights simulate looking down the barrel or through the optics of a gun and are a simple but effective way of improving immersion. Battlefield 2 uses a 2D bitmap rather than real 3D view of the gun, but it works nontheless. The extra effectiveness of aiming through the sites is debatable, especially at close range or with automatic weapons. Fortunately, in a good move, the game permits switching weapon modes by re-selecting the same weapon.
The key to success in the game is to organize into squads. If someone invites you, go for it. There's no hassle to them and while you get orders, those are more like objectives than actual orders. As much fun as it may be lonewolfing, a capable squad is far more effective and satisfying. Also, squads are vital to capturing and holding flag points.
Vehicles are more plentiful than in Battlefield 1942, but seemingly more vulnerable. The infantry combat capabilities of the Anti-tank class are not far removed from others, and the bounty of cover and air support makes even the armored vehicles risky propositions. Views are now restricted to first-person only and this gets quite claustrophobic, especially in armor, though the aircraft are begging
for TrackIR support
. Ground vehicles control just as easily as in BF1942, as do fighters, but helicopters can be tricky. We'd recommend a solid joystick for the helos.
The addition of semi-guided - or more accurately, poorly guided - missiles makes hunting down tanks and aircraft as infantry easier. The rocket-toting Anti-tank kit isn't particularly adept at hitting aircraft unless they're staying still, but there are several SAM launchers available. Missiles track to a limited degree where the player points them, but after a while they're liable to lose lock. The important thing is to bring up the sights with the right mouse button and holding the button down the whole time, before and after firing. APCs on both sides also have rockets, which provides the bulk of their anti-tank capability.
Fighters... well, they're pretty boring actually. The American Joint Strike Fighter and the Middle East Coalition's Sukhoi mostly just fly around chasing each other with missiles and guns. Their primary job seems to be air superiority, keeping the helicopters at bay, rather than actual ground support. The helos are where the action is at, with the MEC's Russian design spamming rockets and the Americans having several to choose from. American choppers can fire TV-guided rockets, machine guns, and drop infantry. Capturing flags with helicopters seems rather rare now, since that requires hovering, which is liable to make you a victim for rocket infantry or jets right quick.