After you finish the game, you can play through again. If you'd like to skip a portion of the game on a subsequent run, you can actually pass over the zoo area with a bit of preparation. After you have retrieved the three objects for the gift shop, have one character drop off the object of desire. Then backtrack to the hotdog vending machine while carrying nothing. Pick up another Frankfurter and carry it around with you until you reach the zoo area. Make sure that the character with the hot dog is not leading as you head into the zoo, where a monster will grab the first character that enters. Instead, have the hotdog-carrying character follow and use the meat to lure the monster to the bridge (which in effect allows you to skip an entire puzzle and portion of the game).