I beat the game. Now how do I play with the other characters like Aquaman and Green Arrow? I used my sheilds to purchase the use of the other characters. Do i have to wait until the middle of the game so that I can choose them to play with? Can you choose your characters at the beginning of the game after you beat it? Also, I was looking on youtube at the gameplay videos and I seen someone was using Green Lantern on the first board. How were they able to use him (or able to select other characters) on the 1st board?