In God of War 1, Kratos is an actual anti-hero, a fallen man, filled with remorse for the deeds he has done and the monster he's become. Killing Ares is actually a redemption for him.
God of War 2 fucked up his character bad.
GoW2 pushed his character past the brink into a villain, which I found to be at least an interesting development.
God of War 3 was straight up character assassination. It was so insultingly filled with incongruence and shit writing (Pandora) that it actually keeps me from wanting to play that game, despite enjoying the gameplay and spectacle.