Is the tutorial the only option for the campaign? I completed each part, but not in succession. I'm wondering if another (part of the) campaign unlocks if I complete the tutorial a certain way. Help?
In Cossacks Back to War Tutorial campaign is the only option. There some campaigns in European Wars and Art of War.
You can add those campaigns to Back to War with the Ultimate pack
The pack also includes a fan-made campaign (Over the Horizon).