While playing the game, press Left Analog-stick Down + Right Analog-stick Up, A, X, B, Y.
While playing the game, hold the Analog-stick Left + C-stick Right, then press X, A, B, Y.
Successfully complete the game on the easy difficulty setting to unlock the sketch gallery.
Successfully complete the game on the normal difficulty setting to unlock the background gallery.
Successfully complete the game on the hard difficulty setting to unlock the model gallery.