Castle O'Dwyer Walkthrough.

  Begin Level by ascending large spiral staircase and follow path to dark shaft.  This dark shaft can be lit up by pressing the 3 switches on the wall at the top.  Descend to the bottom to find another switch that opens an underwater door located in the pool in the main chamber at the start.  
   Through this underwater door, swim up and get out of the water the first chance you get, if you follow the other underwater passage, you'll end up in a room that you'll be coming to later on, and find that you can't get out of the water anyway.  Out of the water, press the switch and open the door into a hall.  In the hall, find the switch and open the door beside it, watch out for baddies, enter the room, flip the switch in there, go back into the hall and proceed through the next door you just opened in the hall.
  This door takes you into the courtyard bottom.  Notice a dark alleyway extending from the courtyard, and follow it.  Down the alley a ways to the right is the stable containing many stalls.  One stall contains a door.  Across the alley (opposite the stable) is a crawlspace with a switch in it.  This switch opens the door in the stable.  Enter said door in stable and find yourself in a poolroom.  Notice that if you fall in the water, you'll have to swim an underwater passage and backtrack to the stable.  In the poolroom, jump and grab the closest pillar hanging from the ceiling.  This is tricky...climb around the pillar and align Lara so she can backflip-180-roll-in-mid-air-to-grab on the next pillar.  Do this all the way to a switch in the far corner of the room.  This switch opens a door opposite the door you originally entered the courtyard bottom, so make your way back there.  Enter the new door and kill some scorpions, kill a baddy and climb up some stairs and run past a door on your left...you'll be coming back to this door in a moment.  Follow the passage into a bedroom style chamber with a crack running along the left hand wall.  At the far end of the room is a switch for that door you passed earlier.  Flip it, and head back.
  The door opens onto a balcony overlooking the courtyard.  Hang over the edge and climb to the right. Around the balcony and up to another balcony.  From here, follow the only route to a switch.  This switch opens up that crack along the wall in the bedroom in one spot.  Go through the opening and climb up a wall to the left to a switch.  Flip it.  Climb down and jump across to that purple-ish room, and down the passage.  This takes you to another bedroom style room with a crawlspace leading to a switch.  Flip it.  Go back into the bedroom and through the closet that swiveled open to allow you access to another balcony in the courtyard.  There's another switch out here for you to flip.  This switch opens a door on the ground floor of the courtyard.
  Once inside this door, kill some baddies, and continue to a staircase leading up.  At the second level up, there's a spot where you can hang over the edge and climb up to a vent.  Scope this out now, but don't go there yet. You have to flip a switch up top first...so go through the door at the top of the ascent, and proceed to open up the first door on your left.  In here is the key switch.  Flip it.  Now you can head back to that climb up to the vent.  Once in the vent, climb down and enter the room you just opened and grab the idol.  This idol goes in the spot beside the double-gates in the bottom of the courtyard, and opens the gate.  Go through the gate and find the crawlspace that leads eventually to a switch...pressing this switch ends the level.
