So I finished the second run through, this time I've gotten all the secrets. Well, except for capturing/eating all plants and food...

21 hours. At least 1/3 of that would go to conversation, cutscenes, and movies. And that is without the numurous occasions when I had to... reload the game because I missed the secret frog thing during the motorcycle. (I mean, it is HARD to aim your sniper on a motocycle!)