Kratos does smile ONE time! In God of War 1 for playstation 2, in Pandoras temple right before Kratos takes down one of the cages so he can sacrifice them into the fire and enter Poseidons place or wherever it was. But you know when you have to push a cage uphills and the monsters with the helmets and one sword and a scythe looking thing keep spawning...
actually he did kinda smile once when he (spoiler) stabbed himself with the blade of Olympus in the third game and Athena told him she was dissapointed
Nice job.