Journey's atmosphere is...indescribable. How long did it take to figure out Journey would look like, well, Journey?
Because I was working on Journey from day 1 (Starting about 3 years ago), I got to see it evolve a lot over that span. It was amazing to see the progression, especially visually. There would be days where I'd play through an area and think "this looks beautiful!" And a week later TGC would update the art there and I'd be floored.
So it always looked like Journey; it never had a radically different style from what you see, even in its early days. But it definitely grew by leaps and bounds before arriving at the final product. (Same thing with the music btw; lots of exploration and experimentation!)