It's an awesome game. Every general from the Civil War is in the game, so when you create a new unit you can recruit the particular officer to lead the unit. You can also transfers troops between armies, but it takes time for them to get there, and you need to manage supply depots along the way. There's even a prison system for taking and exchanging prisoners.
Additionally, you don't have to stick to historical scripts. I had Patrick Cleburne leading an army of about 90,000 men out in northern Missouri, trying to enter into St. Louis. If you hold an area (I took Nebraska and Kansas from the union), you can then recruit troops from that area after a certain time. Bad generals like Braxton Bragg were demoted to brigade or regiment commanders. Meanwhile as Cleburne was doing his thing in Missouri, I had Stonewall Jackson holding TN an invading Kentucky, and Longstreet, Early, Stuart, Johnston, etc. defending Virginia.
There are difficulty levels with the AI. I've never won on the hardest level. They also have you invest money into railroads, new markets, create a navy, defend ports, etc. Even disease and desertion can play a factor in your armies.