Unlock the following difficulty levels by performing the corresponding tasks:
DIFFICULTY LEVEL - HOW TO UNLOCK Medium city event difficulty - Complete 10 city events and "Inexpugnable" (Chapter 6). Hard city event difficulty - Complete 20 city events and "Class Trip" (Chapter 8). Medium combat tour difficulty - Complete 8 easy combat tours after "Hell of a Mess" (Chapter 4). Hard combat tour difficulty - Complete 12 medium difficulty combat tours. Insane combat tour difficulty - Complete all hard difficulty combat tours.