(NOTE: The regular pick-ups in this level will include the shotgun, harpoon gun, MP5 assault rifle, and rocket launcher if you don't have them already.)

Pick up the harpoons in the alcove. Exit the room and get some more flares in the sunken windowsill on the left. When you pick them up, you see a wide-angle view of the scuba diver in the room beyond. Continue along the hall through the next doorway. On the left there's a door marked "Restricted Area." This doesn't open yet. Follow the hall around to the right. On the right side there are windows looking out over the sea bottom. Here you can see a second yellow tunnel running parallel to the one you're in. The second tunnel has a big hole in the side.

FIRST POOL AND SURROUNDING AREAS: Go through the door on the left. Kill the sniper in the raised hallway across the pool. If you don't get him, he runs off to the left. Go around the pool and use the wheel on the wall. This opens the "Restricted Area" door you saw earlier. (You can see this happen through the window.) If the sniper is still alive, he'll come through that door and around to where you entered the pool room.

Before going up to the ledge where the sniper was, jump in the pool and do some exploring. To get oriented, begin treading water facing the doorway where you came in. Swim down and forward, under the yellow overhanging edge of the yellow structure, then up to a rock ledge underneath some netting, where you'll find a bunch of harpoons. Get them and swim back to the pool to breathe.

This time start with the entrance behind Lara. Swim down, then to the back left corner of the underwater area. Swim up through the square opening, and pull the lever in one corner to open the white bars. This draws the attention of a scuba diver who comes out from behind the gate to see what's happening. Harpoon him or swim through the connecting tunnel into the room he came from, climb out of the water and shoot him from there. Pick up some goodies around the edge of the opening: harpoons and 3 boxes of shotgun shells. (NOTE: If you don't yet have the SHOTGUN, you'll get it here in place of one of the boxes of shells.)

Swim back to the big pool, climb out of the water and exit into the hallway. Go to the right to the "Restricted Area" door you opened earlier. Pick up a small med-pack on the ledge just inside on the left and MP5 clips the far end of the hall above the pool.

SECOND POOL (OUTSIDE CAGE): Near those clips is a short ramp above a pool. Slide into the water, find the lever to the left of the underwater gate and pull it to open the gate. This sets off alarms and alerts 2 scuba divers. If you want to, swim out of the cage, forward and up under the yellow structure. Here you can climb out of the water and shoot the divers from above.

Inside this room you'll find harpoons and flares on the low ledges. Press the button in one of the alcoves to open the white gate outside. Find the movable crates (they're green) and pull the one on the right to the right. Go around it and slide the crate on the left in either direction. Go into the alcove behind it to pick up a small med-pack and get a glimpse of a sentry on duty beyond. Notice the goodies behind the fence in the corner with the yellow boxes. You'll be getting them soon.

Jump back in the water and swim down toward the cage where you entered this area. (If necessary get air inside the cage.) Then swim up between the cage and the yellow structure. Pick up Uzi clips on the yellow ledge just above the cage door. Turn right and swim along the side of the yellow structure into the square opening beyond. Follow the twisty tunnel and pick up 2 bunches of harpoons on the way. When you come out the other side, a pair of friendly dolphins greet Lara. (This path is marked with red arrows in the diagram.)

The camera will show a wide-angle view of this area as the current carries Lara to the left. Don't fight it. Look for a square opening near the corner and swim inside. At the end of the tunnel, go left and climb out onto a ledge. This is secret #1, harpoons and 2 large med-packs—the goodies you saw from inside the crate room. (NOTE: If you don't yet have the HARPOON GUN, you'll get it here instead of the harpoons.)

Go back into the water and swim forward to another opening where you can surface. If you linger near the opening, one of the friendly dolphins will give Lara a boost onto the ledge. (How cool is that?!) Immediately draw weapons to kill the sentry you saw earlier through the fence. Take his MP5 clips. (NOTE: If you don't yet have the MP5 ASSAULT RIFLE, you'll get it here instead of the clips.) Then jump off the ledge into the water, where you'll find more harpoons and a small med-pack. The ledge is too high to reach from the water, but there's a break in the netting at one end, where you can swim back to the pool where you started.

Get air in the crate room. Now head for the gate you opened before (using the button in the crate room): Start with the green crates on Lara's right and swim down and straight ahead to the gate. The current sweeps Lara up the tunnel into the next area.

THIRD POOL (SEA CAVE WITH CRANE AND SUBS): Swim straight in from the opening and up inside the yellow funnel to the crane control room where you can get air. Climb out of the pool and pick up a large med-pack and harpoons. If you look out the window, you'll notice a sub descending and releasing 2 scuba divers. Also take note of the two receptacles, blue and yellow, on the other side of the room.

You can swim down and draw the divers up to this opening to kill them. Or go head-to-head with your harpoon gun. After killing the divers get air and make a few forays into the pool for goodies, coming back to this opening for air after each one.

First face the tunnel where you entered from the previous area. Swim down toward it then up to the top of the yellow structure to find some grenades.* There's also a rocket on top of the metal beam the crane is supporting.

(NOTE: The water currents on the side of the control room near the small submarine prevent you from swimming up on that side—and from reaching the sub.)

Take another swim from the control room down toward the crane, then up the rock wall to the right of the crane, where you'll find a small cave. Inside there are flares and a CIRCUIT BULB. Return to the control room for air.

Now swim down to the bottom then up the rock wall, staying to the left of the crane as you pass it. Beyond the crane there's a wide support pillar with round grates and the "Slinc" logo on it. Swim past this toward a rectangular rock pillar. Now head for the ceiling. Just above the rock pillar there's a small, square opening in the cave ceiling surrounded by rusted metal. Swim in here for air and pick up a small med-pack and a second CIRCUIT BULB.

Swim straight down from the small opening toward the globe light below and pick up a bunch of harpoons. If you have enough air, turn left and swim back to the control room (follow the globe lights along the sea bottom). Or swim back up to the small opening first, then return to the crane control room.

Place the two CIRCUIT BULBS in the receptacles on the wall. This opens a small, yellow door on the far side of the underwater cave marked "Restricted Area." Swim down, then up past the crane, following the globe lights on the sea floor toward the door you just opened. When you near the large cave opening on the right, the current sucks Lara down and you see another submersible descending to deliver 2 more scuba divers. If you need air, head for the small opening in the ceiling of the cave. Then confront the divers.

When the coast is clear, approach the small door you just opened but instead of going in, swim into the narrow tunnel just to the right of it. This is secret #2. Follow the tunnel to a cave and go straight through the cave to an opening in the floor. Swim along this tunnel to a room where you can surface and pick up 2 bunches of harpoons and a small med-pack. Swim back out to the secret cave and pick up the flares on the bottom. Be careful when getting the shotgun shells nearby. When you take them, a small submarine speeds down the hill, hitting Lara unless she gets out of the way in time. So position Lara facing either wall, pick up the shells and quickly swim forward out of the way.

When the sub crashes into the wall, it opens up a way into the cave beyond. Get air first if you need it, then swim inside to find the rusted hull of a sunken submarine. Pick up the DESERT EAGLE PISTOL and 2 sets of clips on top of the sub. There's a small, square hole in the ceiling above the left end of the sub where you can get air.

Swim out of the cave, turn right beyond the small yellow sub and follow the tunnel out to the main cave. Make a U-turn to the right and swim through the "Restricted Area" door. The current will carry Lara along to the top of the passageway.

(NOTE: Alternately, after using the CIRCUIT BULBS to open the door, swim directly to the door and go through, avoiding the divers but missing the secret.)

CONTROL ROOM WITH RADAR SCREEN/UNDERWATER AREA WITH SPARKLING MUTAGEN: Swim up to the yellow opening at the top of the passageway and climb out into a hallway with bars at the far end. About halfway down the hall on the left is a room with a window and a locked door. Draw pistols and make some noise to get the gunman's attention. Kill him when he opens the door.

Go in and pick up a small med-pack and flares inside on the right, plus a bunch of harpoons behind the radar screen. Mind the trapdoor in the middle of the floor. Press the button near the door to open the bars at the end of the hallway.

(NOTE: If you fall through the trapdoor, swim back to the yellow opening: Face the white building and swim to the far right corner. Swim through the small, square opening underneath the rusted metal support. Turn left and swim upwards.)

Exit the room, turn left and continue into an enclosed walkway overlooking the sea floor. Each of the 2 red wheels on the right opens one of the small doors on the cave wall outside, letting in 2 huge mutant fish. If you like, you can turn the wheels one at a time so you don't have to deal with both fish at once. (I was hoping they'd fight each other, but they don't.) Continue along the hallway and pick up a rocket and a small med-pack—and get a glimpse of another rocket and the goings-on inside the RESEARCH LAB. (NOTE: If you don't yet have the ROCKET LAUNCHER, you'll get it here.)

Return to the control room and fall through the trapdoor into the water. Harpoon the big fish, or get their attention then swim to the yellow opening, climb out and shoot them from the ledge with pistols. (The small opening from the control room into the water is too far below the floor to climb out, though you can get air here.)

Before going into the RESEARCH LAB, make a few pick-ups: From the yellow opening, swim down and through the small square opening back into the underwater cave. Swim in a little ways then turn around. Swim behind the dark bluish rock to the right of the rusted metal support. Here you'll find some harpoons. Get air at the yellow opening or by swimming up the white funnel to the opening below the control room.

Swim across the underwater area toward the white enclosed walkway. Swim down between the leftmost support pillar and the one next to it. Here you'll find a narrow tunnel in the rock wall. Swim inside to get the attention of another mutant fish. Draw it out into the open area to harpoon it. Or lead it back to the yellow opening and kill from the ledge. After you've dealt with the fish, swim back down the tunnel into a small room with a window looking into the RESEARCH LAB. Pick up a large med-pack, grenades and the loaded GRENADE LAUNCHER.* This is secret #3. Swim back out to pool and up the white funnel for air when you're done, and if necessary between pick-ups.

Now head for the small square doors you opened earlier using the wheels in the walkway. Swim through the door on the right and pick up the MUTANT SAMPLE. Swim through the left door, get another vial of MUTANT SAMPLE and continue along the tunnel to the lab.

RESEARCH LAB: Surface and climb out of the water. Follow the ramp down to a room with tanks and cages containing various mutants. (NOTE: You can see the area where secret #3 is located through the window. If you haven't gotten it yet, you can still go back for it.)

Move the 2 green crates. Underneath one you'll find Uzi clips. Behind the other is a machine. Place one of the MUTANT SAMPLES into this machine. Place the other sample into the identical machine in the other corner. This causes water to flow into a pool elsewhere. (Notice the goodies on the ledges in the cut scene.)

Return up the ramp to the pool where you entered the lab. Go up the stairs, take out the gunman on duty there and grab his small med-pack. Follow the walkway around the edge of the pool. Climb to the upper walkway and pick up the rocket you saw through the fence earlier. Climb up to the small ledge above and get some grenades. Then jump into the pool.

Pick up the HAND OF RATHMORE artifact from the low pedestal. This opens the door in the side of the pool. Get air if you need it, then swim through that door into a dolphin tank. Pull the lever on the left wall to open the door at the other end of the tank, letting in a mutant fish. Harpoon it or lure it up to the first pool, climb out and shoot it. Swim down into the mutant fish's tank. You'll find Uzi clips on the bottom of the tank at the far end.

Swim through the opening in the ceiling of the mutant fish's tank. At the top, climb out onto a floating sub. Step off the edge toward the inflatable boat to end the level.

*NOTE: Before getting the grenade launcher, each time you pick up a pair of grenades it only counts as a single item in your inventory. Once you get the launcher, each pick-up counts as a two grenades, including the ones you've already collected.