On any level in the mines, save your game and turn off the DS, then restart it and load your data. You will load onto the floor you saved on, but all monsters will be GONE. Please note, if you progress any further in the mine, all new monsters will sometimes be INVISIBLE, but are still there (the mines reset after you leave, so it isn't permanent). This is really useful when getting to deep floors and being able to get tons of items hassle free.
10/6/2006
Make mine monsters disappear {NA version only}
When in the mines, save the game and turn off the system.When you turn it back on and reload, all the monsters will be gone! {Please note that unlike the JP version there won't be any invisible monsters.}
2/20/2007
Memory Game
Early in the morning at 6 AM when you first wake up, step outside the house and immediately come back in. Inspect your clock to see if it says "6:01." If it does, inspect the set of records on the shelf to begin a very challenging memory game! Beware, as you must have a sharp mind if you wish to beat it without cheating!