How do you get all of the characters to move/fight on Narnia Prince Caspian for PS2?

[honeygirl0511]

My son is obsessed with his Narnia Prince Caspian game for PS2. He saw a clip on youtube where the characters are able to move around when they go to war, and where they are able to fight, but he is unsure how to do this. Bear with me, b/c I do not play the game and have no clue if I'm offering enough info for you to answer the question. Does anyone know if this is possible? My fear is he saw a commercial or a version of the game for another system, and that he does not have this option.