Cheat mode:
Press Select, Square(2), Circle(2), Triangle, Square, Triangle, Circle at the main menu. A cheat menu with "Invisible" and "Silent" options will be unlocked. Turn them on and enemies will not see or hear you. Select "Continue" to access a level selection screen. Press Left or Right to choose between levels.

Hint: Level 1: Bomb:
When searching for the bomb, there is no need to panic when you find it. It is not a bomb, but is really an alarm clock. You will find it under a picture behind a different colored piece of wood.

Hint: Objects:
When you get an object always search it by pressing X in the inventory screen. You never know what you will find. If you get stuck, try mixing objects with each other.

Hint: Tile puzzle:
In the level where you are in a room with lettered tiles on the floor, spell out M-A-U-R-I-C-E without touching any other letter to open the door. Be prepared, because when you go through there is a little sliding puzzle that must be solved.