Rename a guest to the name given for the desired effect.
At the main menu press: UP, UP, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, UP, UP, DOWN , DOWN, LEFT, RIGHT, LEFT, RIGHT. All animals, foliage, buildings, etc.. will be unlocked once you start the next game.
There are four bonus scenarios that are unlocked by completing a scenario under different difficulty setting (beginner, advanced, etc.)