Way to the Locked Door

Climb up the step. Again, turn left. There you will be attacked by a ninja. Kill him. Turn right. You'll come back to the hall with the columns. There you have to kill another ninja. Run towards the pit. There you'll meet two more ninjas. One from the front and one from behind. Make a running jump to get over the pit again. Now climb into the gap in the left corner. Follow the passage behind. Use the key to open the door.

The Hypostyles Hall

In the hall behind you'll encounter two more ninjas. Kill them. Turn left and collect the uzis as well a small medipack. Run through one of the doors into the next part of the hall. Collect the red shotgun ammo on a square in the middle. Now continue to the right. Climb over the stones at the opening on the left and collect the large medipack in the chamber behind. Climb back out. Now jump up and climb into the opening overhead. Run to the other door. Jump up, hold on to the ceiling and monkey climb along. Climb to the right. At the wall, position yourself above the lever. Let go and press action to use the lever. Get your guns out and shoot the ninja climbing towards you. Then drop to the ground and collect the flares. From that rock you can jump up and climb into the next opening. Run to the other side. In the opening jump up and hold on to the ceiling. Monkey climb to the left and towards the elevated platform. Climb further till you have a platform underneath you. Let go turn around and shoot the next ninja following you. He loses blue shotgun ammo. Run towards the wall and collect the uzi ammo on the left. Then run to the right and climb up. Run towards the pillar and jump around it.

Huge Boulder

There you'll see a huge boulder on a column. Shoot at it. It will then drop down and open up the floor. Climb down. Drop into the hole in the floor. Crawl into the passage ahead and collect the uzi ammo. Now follow the other passage. (On the left, you'll come to a room with a strange mechanism with a chain. There are three beams in the chambers ahead to the right and to the left; they have a pointed end on one side. This is the side that has to be pointed at the pyramid. Leave it alone for now.) Follow the passage ahead. Turn left and climb up the ladder.

The Mechanism

There you'll find a wheel. This will turn the beam in the chamber underneath. Turn it clockwise once. Now run to the next chamber. You have to turn the wheel there twice into any direction. Now run to the next chamber. (Keep in mind you're now facing the other direction so don't head back to the entrance.) Turn the wheel there anticlockwise. Now head back to the entrance and climb back down. Now enter the chamber on the right. Pull the chain. (This will activate the mechanism and the pyramid will release an artefact.) Climb onto the pillar and collect the Sun Disk. Climb down and into the hole in front of the middle beam. Follow the passage.