The game currently offers seven robustly featured cooperative missions that can be played by 1-4 human players against sophisticated AI. These missions take place on battlefields that are generated procedurally.
Although you can play the game solo right now, the game is "realistically challenging." In other words, just like real combat, it's difficult to survive on your own. The game does not currently offer AI teammates to help you, although these will be added in the future.