The campaign is 6 games that each have a different feel. Some are with only 6 enemies instead of 9, some have the enemies that are mostly artillery and infantry, some don't use commander or advantage cards, etc.
The first 5 games of the campaign will have assigned player cards. The sixth allows the player to choose any player cards to use.
Another rule of the campaign is that each game will use a different commander card (player choice).
The campaign is a solo campaign, not 2 player co-op.
The intent of the campaign (in addition to being a campaign) is really to demonstrate all the different ways the game can be played other than the "official" way: against 6 enemies, 8 enemies, 9 enemies, no commander cards, no advantage cards, or any combination.