Here's Game|Life editor Chris Kohler's God of War: Chains of Olympus clear time. (You can view the full screenshot at Game|Life.) You can add on roughly another half an hour to this, as Chris played the first half of the game on a preview disc and then had to start again on the review code.
But even then, Chains of Olympus is still really short at just under five hours. Chris would be a little more forgiving of this if the game was jam-packed full of holy-shit moments like previous God of War games, but it just isn't.