Climb up the vines on the side of the building to the right. You'll then get controls on how to jump to the vines across from you - tilt back and press . Press twice for a double jump. Climb up the next set of vines, then jump back across, climb up, and jump back across to the platform with two chests. Watch the cutscene that follows to be introduced to Wraiths. Fight them, then go up the stairs to the rooftops. Here you'll be encountered by more Wraiths and a Cyclops. After defeating them, go forward and to the right for two chests. Now go back down the stairs and go to the path opened by defeating all of the enemies.
Now you should be facing a new path leading to columns with vines. Go back and open a chest containing experience. Then go forward, jump on the first column, then jump onto the vines on the next. From here, go around to the left of the column and jump onto the platform leading into a building. As always, smash through the door and go inside. Follow the path and defeat the Wraiths, and you'll eventually reach an outdoor area again. Kick down the board with and you'll be able to walk to another porch. Get the experience here, then jump onto the column with the vines, jump to the next, and eventually reach land.
Retrieving Zeus' Fury
When you reach a building with columns and a familiar-looking mechanism on it, go up to the machine and push it. It's a machine that shoots arrows, but you won't be doing that just yet. First, you'll have to take it where you want it. Push it down the path (speed things up by kicking it) and you'll find yourself in a room with two doors. One that needs an arrow to be opened and another that can be lifted. Unfortunately, you can't open the door at the end of the room just yet, since the machine is facing the wrong way (and Kratos can't turn the thing, apparently) so you'll have to take the long route. Start off by pulling the mechanism onto a circle in front of the door you can open at the moment. Then lift the door open by tapping repeatedly. Kill all of the enemies freed by opening the door, then pull the switch. This will make the circle turn and so will the arrows if you placed them right. Now push the mechanism off, turn the switch, pull it back on, and pull the switch again so the arrows can face the right direction. Now shoot the door open and go up to the lightning bolt for your new power. Hold down to aim and to fire. Now you can move on.
Using Zeus' Fury
Start off by using Zeus' Fury on the Undead Archers on the roof of the building you got the power from. Go to the right, the path opened by killing the Undead Archers, and break the wall there for three chests: one containing a Phoenix Feather, another containing magic, and the third containing a Gorgon Eye. Now go back out and climb the ladder back up to the rooftops. Jump to the next roof after killing the enemies and then smash the barrier blocking your way to the other roof. Before doing that, make sure to go to the roof to the left of this one (accessed by swinging on ropes) and open the chests there while killing the Archers with Zeus' Fury. Now you can continue and break the next barrier to jump onto the ledge of the next building. Go up the path, then talk to the man holding the switch to find out why he won't let Kratos across. Kill the coward using Zeus' Fury and then go across. Open the two chests here for a Gorgon Eye and a Phoenix Feather. Kill the Wraiths, go down the elevator, then continue through the path for a cutscene.
After the cutscene, go up the stairs after the Oracle and kill all of the enemies you face along the way. Go up the next set of stairs to reach the Temple of the Oracle.