It's really neat! You can pledge to back the game for different tiers and each tier has a different reward. The also have flag bearers who carry the colors into battle, and I believe they are adding musicians to help organize the field of battle.
Since the campaign takes place around Virginia and Maryland 1862, you can only join regiments that were active in that area and fought in those battles. You can also choose what type of regiment to join such as infantry, cavalry, artillery, and sharpshooter. The one neat thing about the artillery regiments is they can change what type of ammo they're using just like the real guys can. There is a structured command, with the leader of the regiment, typically a Colonel/Lt. Colonel. His command staff, company commanders, NCO's, and then enlisted men.
Did I forget to mention character customization!

You can change what you look like, so the entire regiment looks like the real deal. A mix of young and old, different faces, beards, hair, etc. Each regiment also has their own flair added to their uniforms so you can tell them apart, just like the real thing.
There are also going to add three-four other campaigns in the future once the game gets moving along out of Alpha and Beta.