You can definitely tell while you're playing it. It's probably the best-looking game I've ever seen and it has a pretty unbelievable amount of content.
Let me reply again, game development in my eyes is insanity personified.
If it's engine or interop, it's wild. It always has been.. We used to have memory and space limits, now we have no limits but time. I adore and praise every game developer. It's a tough field.