Grabbed by Ghoulies Cheats
Get a Platinum Medial in Challenges #1, #3, #5, and #7 to unlock concept art pages.
Finish the game, and you can view the staff credits at the "Features" menu of the game.
Hidden FMV sequences
After finishing Challenge #21 you will unlock the "Original Promo Movie" and "Deleted Scene - Crivens Gives The Chair" options in the replay storybook.
For every five "Rare books" that you find, you will unlock a bonus mini-game challenge at the mini-game screen. There are 100 "Rare books" in the game, which unlock a total of twenty bonus mini-game challenges. There is one "Rare book" in every room of the mansion. Challenge #21 is unlocked by completing the previous twenty challenges with a...
Banjo-Kazooie references 3
Every time you enter the kitchen where Ma Soupswill is located, look on the billboard near one of the kitchen's doors. You will see a picture of Banjo and Kazooie.
Embassy Ballroom Destroy all ghouls
Pick up an object and throw it across the room. You may need to try this a few times, you will soon be able to hit the location where a mummy appears (which has a smiley face). Mummies are invincible, but when he runs out of ghouls he will come after you if you attack him.
Enter the options screen and enable the "Butler's Brew" option. Now if you fall in any room, you will be given an option upon re-starting that room if you want Coffee and Waffles. Press A to select "Yes" and you will have double health.
Banjo-Kazooie references 2
Whenever you fight a "Ghoulie", listen. They often sound like creatures from Banjo-Kazooie.
Embassy Ballroom Freeze enemies
In the Embassy Ballroom the second time, kick the mirrors on the side of the hall to get a freeze can. This freezes the ghoulies and skeletons while you kill them.
Banjo-Kazooie references 1
You can see various pictures and statues of Banjo-Kazooie's "Mumbo Jumbo" in the rooms of the mansion.