Exit the treehouse by jumping off it to the rock slide below. Use the Swamp Map to navigate the dangerous mire. The map is difficult to read at first - the black burn marks and large red crosses are the grassy tufts. Make the first jump off the rock by the swamp. Secret #1 - Before you make the final jump from the swamp, jump off into the left corner and pull up into the small chamber for MP5 clips. Finish by jumping into the forest.

Walk through the forest to the top of the slope and run and jump to the rocks on the left edge for some grenades. Drop to the slope below. Walk slowly into the fog and take out the first of many raptors. Follow the valley through shallow water and climb the rocks at the end. Drop down into the next area and run straight ahead bearing right. Just past the nose of the crashed plane is a cave opening in the floor to the right.

Drop through and climb out the other end to find the MP5 (note: this appears in several places in the game until you pick it up. As well as this here it is also in the plane itself and the compy arena we'll go to later. This is the fastest way to find it). Don't drop into the wide open space yet - return to the crashed plane and go around to the left until you meet another raptor. Practise using the MP5.

Return to the right hand side of the plane and continue on until you see a huge tree on the right. Look behind the large tree to find a dark hallway. At the end of this is a kind of arena with a dead soldier and a dead raptor. The entrance shuts behind you and to exit you must throw both of the switches you'll find in two of the alcoves. When you approach the goodies in this room a small herd of compys appears - take them out with pistols and pick up the medikit and MP5 ammo. Back at the crash site head right up a little slope and watch a small battle take place.

If you don't shoot the soldiers, they will not fire at you. Let them take out the raptor (they usually do) then drop down and head to the right corner of this area, by the waterfalls. Head down the hallway to the right of the falls. In the dark, the hallway turns to the right. As you reach daylight you narrowly avoid the start of another raptor battle. Jump up the rocks on the right to await the outcome. Usually the soldiers win. If they lose finish the raptor off. One of the cliff walls in front of you is climbable. Before starting upwards note that there is a raptor on the branch above your head.

Climb the rockface, then backflip to land on a slope and jump from the slope to the branch. If you act fast you can take out the raptor and not fall off the branch (in theory you could shoot the raptor from below but it's very difficult to get a clear shot and too dangerous if the soldiers are patrolling - unless you're taking them out too!). Walk to the end of the branch near the dark corner and jump across to a ledge there. Jump onto a ledge tight in the corner and then across to the higher branch.

Take care of the live raptor on the other side of this area and jump across to get the Save Crystal. Return to the branch and walk to where it bends upwards. Secret #2 - Jump from here slightly to the left to the highest part of the branch (it looks impossible but isn't that bad if you take care). Come back down and walk to the other part of the branch near the dead raptor caught in a vine. Shoot the vine with pistols and the raptor carcass drops to the stream below. That'll occupy the piranha indefinitely.

Drop into the river and swim beyond the piranha (note the decaying bridge collapses) to find a switch. Pull this to open gates on the river bank and release a raptor. Take out the raptor (from the opposite bank if you're chicken!) and go carefully through the gates towards the dark entrance in the far corner. At least one more raptor will appear as you go through this opening and they're easier to kill in the daylight. Unfortunately, you have to enter the room and the door swings shut behind you.

This is a nasty raptor trap. Light a flare and have a good look round. Note the three switches and the block. Throw a switch, roll, run, and jump to the safety of the block. From there, chase off the raptors in the vicinity, and make sure there are none behind you in the shadows before you hop down to throw the next switch. Each time you pull a switch, more raptors are released. When all three switches have been pulled, jump and grab from the box to reach the upper area. Take Lieutenant Tuckerman's Key and the Save Crystal, and one more raptor will rush you from behind.

Double back to the crash site and go through the dark corridor to where you found the MP5. When you venture out toward the soldier, raptors attack from either side. Roll and run back to the ledge. (Note: for a more 'interesting' experience play the following section backwards by leaving the raptors alive and running across the open area and down the slope at the end - you can always come back for the goodies if you make it!)

Kill the raptors and cross the large area noting the goodies up in the trees. Jump onto the branch from the top of the bank for the medikit and make a trickier jump from the end of this branch to the next for Secret #3 - flares. Return to the ground and run to the end of the large area and down the slope. Disperse the compys that appear near the dead raptor and pick up a small medikit from the blocks at the back. Explore this whole area very carefully. There is a gate nearby (with flares) and a shallow pool at the other side. Through the pool is another gate (more flares) and a large nest. The nest is tricky to see from the outside - you have to jump up some large slopes to realise what it is.

When you take Commander Bishop's Key from his body in the nest, the torch near the first gate (a long way away!) lights, and the door opens. Avoid the T-Rex and head for that torch. Throw the switch inside (more flares) and a distant door opens back by the water pools. You can now stand in safety and take out the T-Rex. If you're playing the 'interesting' version of this section you need to leave the T-Rex alive and dash back across the area to the other gate. When you throw the switch there, you gain access to the upper area (through the first hall) and any raptors in the upper area will come down to chew on the T-Rex. While that's going on, you can go back to the upper area and get the Secret. If any raptors come back up top, it's because the T-Rex lost the fight.

Whether you do it the easy way or the hard way you can pick up several goodies on the steps in the tunnel back to the upper area. When everything has settled down retrace your path back to where you first came upon the plane and killed the raptor. At the end of the dark area to the left of the plane is a low pillar which you can climb onto. Jump right to a ledge and then turn away from the rock face to face the tree. The branch above is a monkey swing but you must jump forward to grab hold of it. Monkey-swing to the trunk and drop. Go left a little way and turn around. You should see that the trunk on this side is climbable. Climb up to the platform and monkey swing along the high branch.

When the camera pulls back, drop from the right side of the swing, not quite at the end of the limb. When you land, get to the climbable rock wall nearby. Climb down the wall and shimmy left under an overhanging rock. Pull up on the ledge and crawl inside until you come to a larger cave. Clamber out of the crawlspace and drop down. Climb into the alcove and monkey-swing to the doorway looking into the large chamber.

This is the start of a fiendish puzzle. Drop off the monkey swing onto the floor of the entrance and drop off this to a ledge below. The first switch is around to the left as you face the cliff wall. Once you throw this switch, climb back to the entrance and monkey-swing to the wall opposite. Drop off the swing and immediately grab the climbable rockface. Climb down to the second switch and throw it. Exit this alcove and slide backwards down the slope, grabbing the edge as you slide off. Climb up and immediately backflip to the central pillar, picking up the Save Crystal.

From the central pillar, about-face and jump and grab the ledge back near the entrance. Throw the first switch again and return to the start of the monkey swing. Take the long route on the monkey swing (it twists and turns a lot and goes through some very dark areas so you may need a flare). Climb down the wall near the dead end. Backflip from the very bottom of the rock ladder to reach an alcove behind you.

Return by jumping to the climbable wall and climbing up to an alcove with an open gate. Diagonally jump right from here to the distant slope and grab the edge as you slide off. Shimmy right until the alcove to switch two is above you and then climb up and backflip onto the central pillar. Once you make it safely back to the entrance, monkey-swing back along the twisting route through to a new chamber.

Your meagre reward for all this work is the Uzi clips here. Pick them up and head outside. Run, jump, and grab the tree limb, then walk around to the entrance hatch on the top of the plane. Inside the plane, dispose of the raptor, pick up the MP5 ammo and use both your keys in the cockpit (either side of the doorway). With the power in the cockpit turned on, check the lower area of the plane. Throw the switch at the front of the hold below and the big gun extends out of the back into the outdoors where a major battle is brewing. Sit in the gun and blow everything away (but note that the raptors can still attack you while you're on the gun). When everything is quiet, look at the structures across the river in the left corner. Fire at the walls there and they will blow open. That's the Crash Site exit but don't rush out before picking up any MP5 ammo on the soldiers bodies and the medikit and Save Crystal near the exit.