general:

If you've collected all 7 Secrets in Angkor Wat, this is a different level from the one you'll enter if you haven't collected them all.

If you are faster than Werner, you can take a few shortcuts over bridges and through open doors. I haven't listed these shortcuts here, but it's very easy to find the path on your own.

if you didn't collect all secrets:

Run into the passage ahead. Jump over the first trench. Climb up the wall. Drop into the next trench. Take the passage on the right. Run through the open gate. (If von Croy has closed it, climb up on the left side.). Climb into the passage on the right. Follow it. Jump over the big trench. Grab the wall and climb up. Follow the passage and jump into the next trench. Climb up, jump back down on the other side and climb up again. Turn around and continue climbing. Run over the bridge and through the open gate. (If it's already closed, stick your hand into the hole on the right wall.). Follow the path to the end of the level.

if you did collect all secrets:

Take the passage on the left. Follow it. Make a standing jump to get over the first trap-filled trench. Make a running jump to get over the second one as well. Make another running jump, grab the ledge and pull yourself up. Take the passage on the right, then the one on the left. Run over the collapsing bridge. Jump when you've reached the end and grab the ledge. Pull yourself up. Lara will start to slide. Jump again. Grab the ledge and pull yourself up. Follow the passage. Climb up onto the rocks and into the passage on the right. Jump into the water. Dive into the passage on the right. Swim towards the surface. Run into the passage. (Don't take the stairs.) Make a running jump to get over the two trap filled trenches. In the following chamber go to the left side and climb out. Now you can take the rope to get over the canyon or you can climb down and on the other side back up again. Climb into one of the windows. Take the door on the left. Climb down. Avoid the boars. You can climb the green wall on the left. Jump into the head of the stone figure. Follow the path.

No Secrets!