Monster Lair Hints & Cheats

Cheat Codes

Unlimited Continues
When entering your initials on the scoreboard enter 68K and you'll have unlimited continues as long as you don't change it.
Cheat Effect
Press and hold Select and enter "68K" Unlimited Continues
Continue
When the game over screen appears enter the following command to continue where you left off:
Cheat Effect
Press left, right, down, up, hold select and left. Continue from where you died.
Sound test.
At the title screen enter the following code to access the sound test.
Cheat Effect
Press and hold I and II then press the run button Sound test

Cheat	Effect
Press and hold Select and enter "68K"	Unlimited Continues

Cheat	Effect
Press left, right, down, up, hold select and left.	Continue from where you died.

Cheat	Effect
Press and hold I and II then press the run button	Sound test

Hard Mode
Play the game, get a high score and get a game over. Do this five times. At the name entry screen input the same name all 5 times. When the hi-score list is populated by the same name, the game will be in hard mode.

Hints & FAQs provided courtesy of GameFAQs.