Monster Lair Cheats for Wii
When the 'Game Over' screen appears press Left, Right, Down, Up, hold Select and Left to be able to continue the game from where you died.
Press and hold 'Select' and enter your initials on the scoreboard as '68K' (without the quotes). Doing this will give you unlimited continues as long as you don't change it.
Play the game getting a high score and a 'Game Over'. When you do this 5 times inputting the same name ALL 5 times at the name entry screen so the hi-score list is populated by the same name the Hard mode difficulty setting will become unlocked.