Final Fantasy used there own Engine.
In this Engine you have two modes:
Strategic and Battle Mode.
The Strategioc Mode is only 2D.
All animated Objects are sprites. When the sprite comes near to you, it will be bigger. When it go far away it will be smaller.
In Battle Mode, there is a relly easy 3D Engine. The Most Special Effects are no realtime effects.
The A5 Engine is Stronger than FF, but you must have a very good story, and some of the best Painters of the World. Then you good thing abou making FFX 