If you want to know how to be Luigi I will tell you. First you finish the game than you go to to the perfil menu and you hold l and R as you open you perfil and you will see Luigi. If you save when you play as Luigi it won't work so you have keep on holding l and R everytime you want to be Luigi and to be Mario just do not hold l and R just do what you always do just go on. I hope this works for you because it works for me. THIS IS ONLY FOR NEW SUPER MARIO BROS AND NEW SUPER MARIO BROS 2 NOT ANY OTHER GAME.