Walkthrough by G&D Productions
Watch the flyby and when you start, pick up the Flares near the statue at the N wall.
Jump into the opening in the floor and slide down. Another flyby shows you how huge this complex is. Go straight and to the right see a blue light. When you walk into to it Lara gets transported one floor up.
One floor up.
Go E and shoot the glass cover and pick up the Lasersight from the pedestal. Behind the balustrade SW is the Shotgun.
Now go to the W and again shoot the glass cover and retrieve the Revolver. Pick up Shotgun ammo SE, behind the balustrade and use the lever that is on the wall. Enter and get a Medipack and Revolver ammo. If you ever run out of Revolver ammo you can return here and find another pick up.
Go back to the bridge and turn left (N) get the Revolver and Sight and shoot a brass ball. Go back to the W and enter those open doors on the right (N). The next doors do opens when you approach and when entering the next room jump up a ledge W for Flares.
Go up the stairs, and use the lever on the right (W). Another double door opens. Go back to the bridge. Run to the E and to the right (S). Run through, up the stairs and through the glowing red object and get transported one floor up.
The Red Museum Key
Grab the Flares. Jump over the balustrade and go N. The guide is waiting for you, run after him to see what he does and when he is finished go to the S side, into the shallow water and in the opening S.
There are two levers in there they both lower some spikes in the room in the N. So make your way over there and use them.
Go back to the S and in the SW, just before the shallow pool is an opening. At the end turn around and climb the ladder. Run over the roof and hoist yourself up onto the wooden bridge.
Go N and climb onto the pedestals of one the statues that are aligned on the wall and from there jump to the roof S. Go to the middle and take a running jump to that small gazebo and get the Red Museum Key.
Green Museum Key
Safety drop down and go over to the wooden bridge and drop down on the roof; climb down the ladder. Jump over the balustrade and into the red glowing light. Run back out this room and use the Red Key on the receptacle on the E wall.
The doors N are open now. Step into the green glowing light and again you are transported.
Go N and be careful as there will be spikes popping up. Keep going and avoid in the next part the flame emitters. In the NE corner is a pedestal and get from there the Green Museum Key.
Make your way back to the green light but for now pass it and follow through and make your way to the other side. Almost at the end there are also emitters and spikes popping up. The pit you see on the right has Secret # 1, KitKat. Climb out facing W and continue your journey. At the end you can place the Green Key. You see a camera shot.
Purple Museum Key.
Go to the zip line and slide down. Get down on the ground and shoot the two nasty dogs. Watch out for those marked tiles on the floor. More dogs show up and when you are at the end of this room is a lever on the right around the corner. If you want another secret go to the N again and find almost near those green spikes an open window on the left (W). Jump to the rooftop on the left and run to the opposite side and jump in the windowsill. Go to the S and at the find Secret # 2, Aza. Of course a very nosy dog appears. Go back to the windowsill and jump to the roof and into the other building, run all the way to the end and jump into another windowsill on the right then jump over to the roof of the building W. Hop over the balustrade and get the Purple Museum Key.
Blue Museum Key
Drop to the ground and place the Purple Key S. The door on your right is open. Enter and watch the flyby. Jump to the other side and climb down the ladder all the way to the ground floor. The guide is waiting for you.
Once down go W and shoot the glass, pick up the Blue Museum Key. Go E and again shoot the glass and pick up a Torch. Go to the pillar NW, stand behind it facing E, back flip and jump onto the pillar. Drop the Torch there (use the 1 key or throw the Torch against the head of the statue and it will bounce back onto the block).
Back to the ground floor and use the lever that is in the NE corner. The guide can be very curious so if he stands in the way, just lure him away and use the lever quickly. Get back on the ladder and get of at the first floor. Jump to the other side (N) and again and pick up the Torch from the pillar. Jump back with the Torch up (S).
Look to the SW and you can jump to that ledge and from there to the walkway again and then next to the fire where you can light the Torch (stand in a corner). Go back to the N and ignite the fire there.
Throw the Torch on the ground and climb down the ladder, use the lever and go to behind the pillar SE and back flip/jump on the pillar with the Torch. Drop it and climb the ladder after using the lever and shimmy around the middle part (as well as the bowl with fire) to get to the pillar. Pick up the burning Torch and ignite both bowls in the same way you just did previous one.
Jump back to the S and use the crack to shimmy to the ladder. You probably better jump first to the ledge N and from there jump to the ladder. Climb the ladder all the way to the top. If you want the last secret face NE and just jump (with Ctrl) toward that balcony down and get Secret #3, Gerty.
Back to the ladder and climb all the way up then jump over the ledges to the exit and go out.
Back to the wooden bridge and half way jump on the roof and get back to the balcony with the red light and jump in.
Get to the bridge and jump into the blue light. In the poolroom place the Blue Key left of pedestal at the W wall. Now finally you can get your hands on the Skibblerz Stone and watch the end fly by.