Defeating Gossamer:
When you have collected all the contraptions in Yosemite Zoo, you will enter the Elephant Pong mini-game. Pong (scare) the elephant. The elephant will get faster each time you do this and scare Gossamer. Get three goals to win.
All mini-games:
Enter ?BN to unlock all the mini-games.
Level select:
Select the Marvin Martian icon at the start game screen, then enter “#OP” as a code.