RTX Red Rock Cheat Codes for Gamecube

CheatCodes
Select the codes section on the options screen, then enter these codes for their effect. If entered correctly, a message will appear. Note: For the Level Select Code, after using it, go to the main menu and hold R1 to display the level selection screen.

Code - Effect:

Right(5), Left(3), Up(2) - All items
Left, Down, Up, Left, Right, Up, Down, Left, Right, Down - All special features
Up, Down(8), Up - Easy mode
Down, Up(8), Down - Hard mode
Down, Left(2), Down, Left, Down, Right, Down, Left, Down - Level Select
Up, Down, Up, Down, Up, Down, Up, Down, Up, Down - Normal mode
Right, Up, Down(2), Up, Right(2), Up, Down(2) - Old soul super weapons