Each mini game is unlockable by finding a hidden icon within the game. Grabing the icons will unlock the mini game. The following is where each icon is located and which game it unlocks:
Aeronauts: Secret room located in level 4
Apple Masher: Secret Room on top of the heystacks in level 3
Bale Out: Secret Room in Zuckerman's Barn
Bounce: Enter the hole in the tree and search in the branches in level 8
Bumper Cars: Ledge outside of the circus tent in level 13
Food Catch: Enter the tires and the icon will be on the tire pile in level 10
Ring Toss: Secret Room outside of the circus tent in level 14
Snacktime for Templeton: Enter the tires and the icon will be on the tire pile in level 9
Spree Ball: Ontop of the Information Booth in level 14
Water Fun: Enter the hole in the tree and search the branches in level 5
Webbing Crashers: Secret room next to the water wheel in level 6
