Only 25 hours of storyline? So this means if you play one day nonstop, without taking any rest, without sleeping, eating, drinking, shitting, or masturbating. And playing from mission to mission without taking time to explore the game environment and all of the cool side missions and activities. And assuming that the player passes each mission at first try (which is unlikely).
I played GTA IV for three months. I sure hope that GTA V will provide months worth of gaming aswell and that the story is even longer than the one of GTA IV.
If merely console version looks so goddamn' good, then I can only imagine how astounding PC version will look.