Turn the wall torch in the "Water" room to open a secret door to the
tunnels.
Follow the tunnel from the secret door above to a lever on the wall
that opens a hatch into the room you climb down into from the tunnel behind
your jail cell.
Frob a fish in the freezer to open a secret door to the tunnels.
Walk down the hallway from the box offices, turn down the first hallway
and look for a switch in the third alcove on the left. It opens a secret
door on the next hallway that leads to the tunnels with spiders and haunts.
The first room you enter from the secret door opened by secret #3
has a floor hatch that leads into an office.
In the tunnels accessed by secret #3, go past the spider and rats
to the area the haunts patrol. Find an alcove in the wall with a ladder
in it. Climb to the top and flip a lever to open a door onto the beams above
the entrance to the box offices.
Push the painting on the center column in the Lesser Liege’s office
to move it and expose a button. Push the button to open a hatch on the other
side of the column. (It looks black, but if you lean just right, you can pick
up a box from the black area.)
Go into the fireplace in the Grand Liege’s kitchen and you’ll find
a button. Go over to the other corner of the kitchen and down the hatch.
Go through and mantle up into the next opening. In here, you’ll find a small
button in the corner that was previously hidden by a cover.
Push the second button mentioned in secret #8 to open a door into
the part of the tunnels patrolled by haunts.
In the Lesser Liege’s living quarters, look under the desk for a lever.
It opens a hatch in the bedroom ceiling.