Corrected entry: Atlas was depicted as a normal man in the first God of war, but in this he is a Titan with four arms.
Corrected entry: In the first God of War, Athena tells Kratos that Cronos is the last living Titan. In this game, the other Titans are still alive.
Correction: They were always alive; it is revealed that none of them were ever killed. Rather, Kratos travels back in time and brings them to the future, at a point in time just before they were thought to have been killed. Since their bodies disappeared, everyone assumed that they had died, but they had really traveled into the future with Kratos.
This entry is referring to the beginning of the game after Kratos was sent to the Underworld where he meets the Titans. Not to when he traveled back in time to bring the Titans to the future. Since Athena told Kratos that Cronos was the last living Titan, when Kratos got pulled into the Underworld, then he should never have been able to meet the other Titans.
Correction: The Atlas seen in the first games is a statue built by the architect of Pandora's Temple, someone who never saw the real Atlas.
MasterOfAll