static void Main(string[] args)
{
string enemyName = args[0];
EnemyFactory enemyFactory = new EnemyFactory();
// now the main class 'program' isn't aware of
// the enemy types anymore (good)
// but its aware of the particular factory (bad)
IEnemy enemy = enemyFactory.CreateInstance(enemyName.ToLower());
enemy.Attack();
enemy.Die();
}