A freeform game in Zoo Tycoon 2 is probably the most commonly used game form. Freeform games allow you to create the zoo of your dreams, with the only restriction being space. The players money supply is unlimited, and all items are available from the beginning of the game play. When you create a new game, you will start off with an empty zoo, ready for development. From there on, you may create animal exhibits and guest facilities (such as restaurants and bathrooms), hire employees, and landscape. This game form is favored for two reasons: First, it allows you to create a zoo, and see if it will do well enough to develop a similar zoo in a challenge game (see below). Lastly, there are no money restrictions, which allows you to buy without waiting for your profits to increase.
Challenge games are the equivalent of previous Zoo Tycoon freeform games. In this type of game, your money supply is limited, and not all items are ready for immediate use. Game play is the same as freeform with the exception that you must try to make a profit in order to keep your zoo running, and you must research certain items for them to be available for use. This mode will occasionally give the player challenges such as "take a photo of a young giraffe calling to it's mother".
A scenario game (also called a goal game) is a game form in which the player must complete a goal to win. When you start off, you have certain tasks to do (e.x.. Create a New Hippo Exhibit, Get a Blue Ribbon Award). Once you have completed the tasks, you unlock another scenario in which there are more goals. To win the scenario games, you must achieve the tasks in the last scenario. The scenarios are as varied as just running a zoo, to creating and managing a five star zoo for 4 years.