The best Civil War strategy game to ever appear on computer- bar none. If you like the subject, this is a must buy.
You are essentially either Lincoln or Davis. You can play shorter scenarios and some battles (which are in and of themselves not a stand alone feature) but the 1861 to 1866 Campaign is where AACW (AGEODs American Civil War) shines. Turns are 2 weeks long and this seems just about right for the subject matter. The map, which is beautiful by the way, is broken into states and regions (counties).
You get to decide on investment, recruiting conscripts, money, political options and civil liberties in states under your control (this is not as difficult as it sounds, although AGEOD is known for not explaining the "why" behind a given feature of the game). Then you move existing units and raise new ones, everything from militia to signal corps and all sorts of artillery to river and ocean naval vessels.
Your most important asset is your military leaders. With these you form basic unit "stacks" (i.e., brigades) or if you have a proper 3-star leader, form an Army and then attach Corps to it with other 2 or 3-star leaders. Leaders come with arrival dates and most but not all have "traits", some good, some bad... they are also rated for Strategic/Offensive/Defensive. Strategic essentially tells you how often they will activate in a given turn- in other words, how often they can participate in an Offensive action or move without a penalty. Part of the fun is building all your various elements into Corps and Armies. Stacks that are not part of an Army are deemed "not in command" and suffer some penalties that can be detrimental, but not always. Irregular units like Rangers and Indians can operate alone just fine. Forming armies is the #1 contencious issue for a lot of folks with AACW as it can be non-intuitive for many- but mostly it just takes some getting used to it to feel comfortable.
One aspect that could possibly turn off some folks is the "arms length" combat in the game. You move units into regions (~ equivalent to counties) and if you meet the enemy and the game determines you find one another, a battle ensues. All you are shown for a given battle (which happens on a particular day of the 14 day turn) is a synopsis of who was involved, what happened from many standpoints, along with lots of mouse tooltip details to let you know what it all means. If you just HAVE to have tactical control of each unit, this WON'T be the game for you.
But if you enjoy building your nation and hoping you assigned the best leaders for the job at hand, dive in! There are many events that have a % chance of occuring. The St. Louis Massacre is one. If it happens (50% chance) then the Union gains leader Lyons in St. Louis, and the Confederates will get Price in Missouri, the same as historically.
Another strong point of this game is the support the French company (yes, French) has provided. There is internal support within the game for mods and two big ones right now are a Leader Optimization mod and a Weather mod. More are in the works on the forums.
I could write a whole lot more, but as I said earlier, if you have even the slightest interest in the American Civil War on a Strategic level, this is a MUST BUY.