Enter B, Up, Left, Down, Right, B(2), and make sure you don't have any special weapons. Do this when you're playing the game to get the best version of each weapon. Enter the cheats using the D-pad.

Enter Down(2), B, Y, Down(2) when you're playing the game. (D-pad)

Enter Left(2), B or Right(2), B during game play. (D-pad.)