found a bug. When you disband a cannon, then try to put up a puck cannon in its place, you can't, it says you can only build a puck cannon on an empty bastion . . . but it is empty.
Game seems ok. I am a fan of card games in general. I cannot seem to figure out the evolve bit, which I'm begining to think plays a rather important part of the game. I'll check back from time to time to see if there are better in-game instructions.
 "Master of Fortresses"){kind=icon}
 "3D Logic"){kind=icon}
 "Mystic Cards"){kind=icon}