Curious how long it will take to fully beat the Final Fantasy 15 story? Well despite the large open world displayed and showed so far, it will only take roughly 40-50 hours of gameplay to beat. But if you wish to fully beat the game, then you're looking at 200 hours!
I think that sounds about good for the game. Personally I prefer my games to last no more than 40-50 hours storywise, and I'd prefer to completion being achievable within 100 hours, but I guess if the other 100 hours is not just mindless grinding then I could bother with it.