Slide down and jump across the gap at the bottom. Push the boulder to the right, and then quickly hop back to the left to avoid being crushed by the tree. Continue to the right.
Jump on the large rock here and use it to traverse to the other side of the spike pit. Be sure to keep jumping towards the entrance to prevent our silhouetted hero from falling down. As you cross the gap, you will see thespider re-appear on the ceiling, so be ready to jump from the rolling stone to the far ledge as soon as you are able.
Slide down the hill and continue to the right. You will see a dead body, walk towards it and the ground will give way. Ahead you will see a rope with a trap attached to it. In order to use this, jump to the rope, then quickly jump off the rope. This will dislodge the trap and allow you to use the rope safely.

