AirLand is a highly time consuming, and addicting RTS. Not so much in the battles themselves, but in designing army types. From armoured columns to air forces, the customisation of your "deck" of units is mind boggling.
The battles in and of themselves are simple enough in their objectives, however the outcome will depend heavily on tactical thinking. Classic military strategy pays dividends, using infrantry and support (be it artillery in the form of rockets, howitzers and mortars, or light vehicles) as an anvil, and MBT's, ground attack aircraft and assault helicopters as the hammer. However, the incredible variety of units can be used to great effect in less conventional ways. Inserting commando squads (which vary by the 12 nations) to systematically remove your enemies' anti-air capabilities, followed by saturation carpet bombing by low level attack planes, can be very effective.
In the end, the tactics of each player will vary wildly depending on thier choice of units and nation.
As for the games requirements and such:
A touch of a memory hog, though there is a lot of game here. Not too hard to run in very pretty settings, and easy to pick up and play, assuming you have some grasp of military tactics and equipment. A good singleplayer experience to be sure, but the game shines most in multiplayer, when coordinating with your allies in calculated joint attacks.
Better than most, Wargame is a solid RTS, well worth buying, especially if on sale.