Various cheats

All Creatures
     At the Main Menu press Left, Right, Left, Left, Right, Right, Right, X

All Multiplayer Maps 
     At the Main Menu press Left, Right, Left, Left, Right, Left, Right, X

Get Crystal 
     At  the  in-game  menu  press Left, Left, Right, Right, Left, Up,
Right, Down, Left, X, X

Invulnerability 
     At  the  in-game menu press Left, Left, Right, Right, Up, Up, Up,
Up, X, Up, X

Win Mission 
     At  the  in-game menu press Left, Left, Right, Right, Down, Down,
Down, Up, Down, Down, X