static void Main(string[] args)
        {
            Generator[] generators = new Generator[2];
            generators[0] = new Stage01Generator();
            generators[1] = new Stage02Generator();

            foreach (Generator gen in generators)
            {
                Console.WriteLine("*** {0} ****", gen.GetType().Name);
                gen.CreateEnemys();
                Console.WriteLine("\n");
            }

            Console.ReadKey();
        }