Unity is a multiplatform game development tool, designed from the start to ease creation. A fully integrated professional application, Unity just happens to contain the most powerful engine this side of a million dollars.
You are given anything you need to create the gameplay for your game. Both 2D and 3D. Most features in the Pro version are for creating better visuals. It is possible to do advanced graphical features without Pro version, but then again, the performance might not be as good as Pro counterpart.