[jyxqfykv] Fortress attack and defense

Air power, including missiles and bombs, have rendered the fortress obsolete.  However, it is fascinating the amount of technological sophistication developed as means to attack and defend fortresses (and variations such as castles and walled cities), for example, the trebuchet.

Bring back that concept of open-ended design, perhaps in a game or contest.  The problem is to keep it balanced: still need to forbid air power.  Is there some meta-mechanism to keep it balanced?  Perhaps some sort of resource allocation to the losing side each round.