Kratos was made into a God, but memories of his past have not been erased. He seeks vengeance and raises havoc on Rome with his Spartan army. The gods are displeased with him and warn him that if he continues on this path, they will no longer help him. Kratos does not take this seriously, and as a result he is turned into a mortal. This is where the game begins.
After Kratos becomes mortal, he shrinks in size and ends up in a Roman castle. You will begin by encountering a few soldiers. Kill them all and exit the room through a gated door by using the R1 button and pressing the O button several times. Consistent with the original God of War game, the game controls are the same. Enemies will also emit red orbs when killed (which can be used later for upgrades). Depending on the level of difficulty you are playing, there is a tutorial/hint feature that will assist you in learning how to do certain actions. This is optional and can be shut off.
Anyway, after exiting this room you will encounter a Colossus. He will try to attack you. Initially you will just avoid his attacks and move away from him. After a while you will have your first mini-boss battle with him. There are two platforms. On the first platform there are soldiers that will attack you repeatedly while the Colossus slams his large arm and hand on the ground to try and cause damage. Attack his arm to cause damage and stun him. Once he is stunned, go to your left up on the other platform with a ballista. Use the R1 button then the O button to shoot the loaded stone at him. You will need to stun him a couple of times and go back to the ballista. The last time you stun him in this round causes an animated sequence to begin. Watch for controller button actions. As they appear, you will need to be quick or you will have to stun the colossus again. When you succeed in this task, the colossus then throws you into another area where you will fall into some water.
In this area you begin underwater. You will need to swim your way through a blocked gate. Use the R1 and X button to speed your way through this barrier. Then go to the surface using the triangle button. Once out of the water you will see a ladder. Go up and save your game at this saving spot. To the left of this is a lever that will activate a machine that carries some objects on hooks above you. One of these hooks will stop nearby you. Swing over on this hook to the other side (R1, then X to let go).
Moving forward you will encounter more enemies. Get past them and you will see a broken ladder ahead of you. Climb up and then move up the wall to your left. Once you are at the top you will then have a second mini-boss encounter with the colossus.