What a way to start a level - Stripped of all your possessions and locked up! First we need to get Lara out of this jail cell then find her weapons. There is a switch which opens the cell door but it's on a timer so before you go flipping it you had better clear an escape route. When you have pushed and pulled the crates so you have a clear path to the door, go pull the switch (which I hope you have found by now).
Once you escape the alarm will sound and the bad guys start to show up. The first one to worry about is coming from your left. Head off to meet him, and get past him so you can lead him back to his starting location. Dodge his gunfire and also the blows of his friend who is also waiting here. Try to draw his gunfire so he blows out the nearby windows which you can promptly escape through. Head right along the narrow ledge and press the button on the wall to open the bay doors beneath the plane. Swim inside and go over to press another button to kill the plane's engines then return back through the broken window and do a running jump and pull up to the top of the engine. Drop into the trapdoor on top of the plane to find your lost Pistols.
Go back and kill those two bullies who were giving you a hard time earlier and take the Yellow Key Card. Go back through the broken window and head left this time to a room with some water. Dive in the water and flip the switch beneath the tunnel opening which grants you access to the upcoming Secret #1; the Jade Dragon. Resurface and fill those lungs for a long dive. Enter the tunnel and follow it left then right and then a sharp right then take the downward passage staying near the top so you can get behind the underwater fan. Grab the dragon statue and swim back to the surface to catch your breath before heading back to the door with the Yellow Key Lock.
Enter the next room and press the button on the far wall to kill the alarm. Go up the stairs to the right and spin the wheel to open the door. Kill the rig worker and take his medkit then proceed into the next room and kill another workman who is coming down a ramp and through a door which locks as you near it. Spin the wheel to open the next door and kill a guard and get some ammo and your first batch of harpoons.
Enter the bunk area and reclaim your Auto-Mags from the right top-center bunk then go to the end and get the Harpoon Gun from the last bunk on the left. Go back to the entrance of the bunk area and press the button above the top-left bunk to open a door in the ceiling at the opposite end. Run to the top right bunk and climb on and jump and grab to the opening to gain access to the passage above.
Continue down the hall and slide backwards down the ramp so you can grab on and use the ladder to climb down to the floor. We need to use those boxes to get past the 4 burners and reach the ladder on the other side. Pull the first one to the left all the way past the other box then go push the second box towards the burners. Now you can do a running jump and grab onto the ladder. When you reach the top of the ladder, head to the right and kill another guard who also happens to have the Red Key Card on him. Climb the ladder to get Secret #2; the Stone Dragon.
Go up the stairs and return to the room with the water from earlier in the game. Now that you know where you are; return to the room with the button that turned off the alarm and go up the stairs to the left of the button. Kill the guard and his dog and take the Uzi clips. The door with the Red Key Lock is at the top of the ramp so jump out of the way of the rolling barrels to make your way to this door.
Enter the door and head left to kill another Rig Worker as another sneaks up behind you and another climbs in from the right. Take the shells, medkit and flares from the resulting casualties then return to the landing near the entrance. Push the box once then go around it and pull it once then go around and push it once more. Now you can go to the opposite landing and do a running jump and grab to pull up onto the box and access the opening in the wall.
Take the shells from the guard you kill in this passage and go to the door with the Green Key Lock. There is also a switch and a trapdoor in this area. Flip the switch to see that empty tank behind you being filled with water. Return and drop down to the floor then swing across the water tank and head right. Go over the pipes then head left until you find a switch on the wall which opens the trap door back near the door with the Green Key Lock. Go all the way back and drop into the trapdoor and slide down the ramp.
Deadly Frogmen are lurking in the water so run to the right and see if you can catch one on the surface and blast him. If you miss him or he's not there, just return to the other end and dive in and get ready for action. Swim toward the pillars quickly as you are being pursued by a deadly frogman. Climb up on the closest pillar using one of the two sides with the yellow stripes and wait for the frogman to surface. Finish him off with your favorite weapon.
The next closest pillar has a ladder which leads to the catwalk above. Before you climb up it, go get Secret #3; the Gold Dragon which is sitting at the base of the pillar at the end of that catwalk where you ran to try and shoot the first frogman. When you claim your prize, two guards will arrive. You can either fight them here to snipe them from the catwalk above.
When you are up the ladder you need to follow the catwalk and do a running jump when you reach the gap. Grab on and pull up and kill the gunman who just happens to have your Shotgun. Take back your weapon then go right and when you reach the central wall, go left and follow the catwalks. You should spot a hole in the wall up above (the Exit) and another bad buy up ahead guards the Green Key Card which is inside a box. Kill him, then jump into the box. You will break through and can now take the card.
Follow the catwalk up to the hole in the wall and return to the room with the door with the Green Key Lock, making sure to kill the guard you meet on the way. Once the door is open you need to flip that switch on the wall to drain the water from the one tank and pump it into the other. Now you can swim through the opening and flip the underwater switch to open the grate. Climb up and head down the passage to the exit...