You start the second level very abruptly. So much in fact, that you come face to face with a big bear. Kill it or it kills you.
You get to a room with two vertical columns.
Jump on the first pole, and go down. Right behind you is a medi-pack. Take it. Now, to climb on the second pole, you'll have to run and jump on the rock (that looks like a ramp) in front of you.
Climb the pole and jump onto the other side. You've just reached the City of Vilcabamba.
Go down the stairs to your left, and on forward. In the next room there are 2 wolves. Kill the mutts!
Go down the stairs at the end of the room.
Watch out, there's another bear in the city. It seems that it doesn't know to climb stairs. It might be a bug in my version. But it's good to know. So stay on top of the "situation" and kill it.
To continue on forward, you'll need a key. The only way is to go underwater. You'll have to be fast. Go through the underwater passage, and pool the lever to open the hatch. You won't be able to surface otherwise, and you'll die!