All parks
While in any park, press X, B, Y, X, B, Y, X to unlock all parks.

All rides
While in any park, press X, B, Y, X, B, Y(2) to unlock all rides.

Extra $50,000
While in any park, press X, B, Y, X, B, Y, A.

Mission completion
While in any park, press X, B, Y, X, B, Y, B. Then at the mission selection screen, press X to complete the highlighted mission and unlock the next mission. Note: Each time Square is pressed on a highlighted mission, the rank of the completion increases (from bronze to silver, and finally gold). To reverse your progression on a mission, press B at the mission selection screen to remove the highlighted mission medal.