While in a park, press SQUARE, CIRCLE, TRIANGLE, SQUARE, CIRCLE, TRIANGLE, CIRCLE. If you entered the code correctly, you will hear a sound. Press Square at the mission selection screen 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 Circle at the mission selection screen to remove the highlighted mission medal.