Unlock the following items by performing the corresponding tasks:

ITEM - HOW TO UNLOCK
Binoculars - Collect it at the end of the Industrial Castle level, after defeating the Boss.
Boomerang - Equip the Cardinal Animal Orb in the Thief Forest level. The cardinal will find it when you find the owl defecating from a tree.
Bow and Arrow - Found randomly in the Thief Forest level.
Compass - Search to the left of the blacksmith.
Horn - Defeat the Corn boss to receive it from a peasant.
Key Weapon - Equip the Cardinal Animal Orb in the Full Moon level. Go up when you reach the mountain path and approach the second hut.
Spade - Go to the first desert level. It is in front of you to the left of the sand castle.
Steering Wheel - Defeat the dragons and go to the end of the lava-colored level.
Treasure Map - Defeat a team in a game of volleyball during a mission at the Sand Castle level.