During two lectures held at Siggraph 2016, Square Enix developers showcased some of the advanced tech and rendering tricks used to make Final Fantasy XV look as good as it does.
While the talks were quite technical, quite a few videos were showcased, featuring the effect of those techniques in areas like animation, weather, lighting clouds and more. You can check them all out below.
Keep in mind that the resolution of some of the videos is unfortunately very low, as they were showcased in a very small window within the slides.
AI Pathing
Physically Based Animation
Yes. The game has food physics.
Animation Graphs
Specular Reflections
Wind Physics
Volumetrics
Cloud Rendering
Rain
Below you can also find the whole recording of the lectures, courtesy of Siggraph (with another upload here, which includes a missing part), and the slides of the presentations, including quite a few interesting work-in-progress images.
Among those, you can see how hair is affected by physics differently when it rains, lighting at different times of day (alternating between indirect and direct lighting and a mix of both), and much more.