One special case to watch out for occurs in games with "unintelligent" units, that is, they have an acp of 0. If a side loses all of its units except for the unintelligent ones, the player will not be able to do anything except wait for the game to end. This might be OK, for instance if the idea of the game allows for a side to own a particular unit, whether or not it can do anything with it (perhaps the unit is a fort, and a side can win if it owns the fort, even at the cost of all its other units). Usually, however, the side ought to just lose, in which case you will need to define a special scorekeeper that requires each side to have at least one of some sort of unit with acp > 0, or else it loses.