The problem is that a prototype is not equivalent to a real fighting system you will put in a game. You will need a lot of testing so the game is challenging is

The problem is that a prototype is not equivalent to a real fighting system you will put in a game. You will need a lot of testing so the game is challenging is fun. And it must be challenging and fun during all the game (30+ hours). EDIT: To give an example, see a website. A small website to show some prototype will be quite quick to do. But when you need to do a website used by hundreds to thousands persons with a lot of use case, it gets far more complex.