I don't know if this is related to Keeperfx or just the Ancient Keeper campaign itself, but I've encountered a couple of bugs which probably should be easy to fix. In level 6 Save the Heroes the green keeper gets no minions, and in level 7 Kwan Tek's ordeal, the blue keeper gets no minions. This makes Level 6 easier and level 7 impossible to win (even killing the enemy dungeon heart does not win the level).