At the beginning of the level, you will see the objective that you need to complete. Add new buildings and enclosures for new animals that you will have to purchase. Although, as the story goes, you will have a chance to change them. You are going to play with the premade zoos here. The more tasks you will be able to finish in a definite period of time, the better score you will get! It is possible to get the maximum of three stars on each level. In the career mode, you will have to complete 42 levels to reach the end. The latter ones can be unlocked with some hacks as well.
And the last one is for those who want to test their management abilities and collect achievements.
The first one will come to your taste, if you want to show your facility to other players. The other modes are franchise and challenge regimes. However, if you already have some experience, you will be interested in a sandbox, where you can build constructions without worrying about money or resources. If you are not familiar with the project and want to follow the plot, you can choose the career mode. Each of them is suitable for a certain aim. The game has several modes that you can select before you begin.