All Spatulas:
Pause the game at the Goo Lagoon and go to the Flying Dutchman's Graveyard. Then, press R2, L1, Square, Triangle, which will resume the game. Press Start again and press L1, R2, X, Triangle, Triangle to get all spatulas.

Concept Art:
Go to the third section of Bikini Bottom. Obtain 40,000 shiny objects. Go to the movie theater and press R1 to enter. Then press X to see the art.

Thanks to Revolution reader William Wailes!