Bunch of mechanics specifically designed to frustrait you in the campaigns. Example: if you struggle to progress in the campaign they TAKE AWAY upgrades on retrys. Making the run harder than the first attempt. This isn't even a paywall thing. It baffles me why they would design features in the "vs Ai" portions that are there solely to upset you. These are preset decks/adventures. No paywall. They aren't even making money off of these anti-progression elements. Incredibly frustrating.