Zoo Tycoon 2 is the sequel to Zoo Tycoon. The sequel updates the graphics, but keeps much of the original gameplay the same.
You start with an open field and must build it up into a zoo. Create exhibits and populate them with animals. Build amenities and concession stands to keep visitors happy in between exhibits. Happy visitors will donate more money to your zoo so you can make it better. However, you have much more freedom in exhibit creation. You don't even need fences; a moat or ditch will suffice, as this technique is popular at real high profile zoos. There are also more animals and attractions to place in your zoo, and animal habitats look as realistic as the cartoony graphics style will allow.