- Total number of secrets: 3
- Total number of kills: 13
- Item pick-ups: 16
- PlayStation save crystals: 3
The valley
Proceed down the passage until you reach a stream; at that point, follow the stream to the right until you reach a series of blocks. Start climbing down, but before you reach the very bottom, draw your pistols and get rid of the two wolves down below (alternatively you can jump in the stream, go off of the waterfall and surface, immediately killing the wolves). When they're gone, climb up the small block in front of the cave entrance (opposite the waterfall) and kill the nearby wolf. Keep following the narrow passage until you reach a cavern with tall block-shaped rocks and a large opening up above. (Note: the passage on the right in the cavern leads to a dead-end area with three wolves: only go here if you want all of the kills; to be efficient, go into the area and immediately jump back, shooting the wolves from a safe vantage point.)
Begin to climb up the block-shaped rocks until you reach the large opening above. Take the nearby Large Medpack and climb down the opposite side to reach a large valley; immediately draw your pistols and kill the oncoming raptor. The best way to kill these enemies is to shoot and jump backwards at the same time, as they'll barely catch up with you when you're jumping. When that raptor's history, keep going forward into the valley, where you'll have to face yet another raptor (but be sure not to go too close to the destroyed bridge). After both raptors are dead, go near the destroyed bridge and immediately into the nearby passage (that goes into the cliff). The ground will start to shake... And a T-Rex will quickly come to greet you. Stay in the passage at all times, only coming out to shoot it a couple of times with your pistols; it will take a while but the T-Rex will eventually die (you can also fight it outside the passage, shooting and jumping backwards at the same time to successfully kill it).
Secret #1: Back in the valley, go towards the waterfall on the right, where you'll notice a small opening to the very right of the waterfall; climb into it, grab the Shotgun Shells to the right and climb back down into the valley.
Secret #2: Face the same waterfall and climb onto the low block to the left. Climb onto the next one and take a diagonal standing jump to the higher block to the right. Grab the crevice currently above you and shimmy to the right until you reach a spot in the waterfall opening you can climb into (which is near the middle); head into the passage on the right, take the Shotgun Shells and Magnum Clips and jump into the pool below the waterfall, climbing out shortly after.