Scooby Doo: Night of 100 Frights Cheats

First go to smugglers cove then go to shock on the dock part II. 
There is a pile of planks near the warp gate.  Do a thunder smash
on it and then you will get to creepy crawlies in the hallways. 

Just set your PS2 system clock to January 1(New years), July 4(US Independence Day, October 31(Halloween), or December 25(X-Mas) and the mystic Lawns ecor will alter to reflect that holiday

If you set the date to February 2nd,when you eat a Scooby Snack, it will have a small flower above it after you ate it.

Beginners, when you get to the place where there are 4 floors, the bottom one topples, so if you don't want the caveman to get out of the ice, simply go through the floorboard PAST the ice block and let it slide you down. this skips the fact that you will get pummeled by the caveman's club. pretty clever, huh? Also, some big enemies are able for you to head butt them (run at them) this will make them dizzy for a while but can get back to normal. But the zombies in the hedge maze, unable to head butt. sorry :(

Change the Playstation2 system date to the following entries for some special seasonal decoration:

When playing the game, go to 'The One Way Trip To the Crypt' level with the warp gate on it. Activate it and go to the warp gate North-West from the one you are on and press X. Even though you haven't even gone into this level, you can get Scooby snacks and beat the Green Ghost. To make sure that the cheat has worked, go down the path where the buttons are and go through the gate. You see the locked gate, but when you go near it, it opens.

During gameplay, press START and enter the following codes. Upon entering the code correctly, you will hear a sound effect to confirm the code.

To get multiplayer plug in another controller and press: R1+ R2+L1+L2+ START hope it works!