if you watch the youtube vidio you should know it was a fake they
did something with the game online there is no waluigi cheat but there is one cheat to prove I'm right go in the front door of the castle now thre should be alittle sun (or star) in the middle of the floor go to it walk in the middle of it and press x and look up
and you should go to a sweet bonus level but this is only for ds!
oh and one more once you get 150 stars you could unlock the cannon
hint some of the secret stars could be gotten in bowser levels or any by useing the star pad or getting all red coins and there might be one more star I can't remember but once you get to the roof on the cannon thres 2 or 3 lifes and a feather so you could
fly around the castle!