Cross the waste pond and take the long corridor on the right, raise the footpath and come up the few steps to the room where the footpath ends. There is two barrels against a bit of wall. Get rid of them, and tap the wall for a secret door. Goodies!

Get out on the footpath and do... well, what would John Wayne have done? On the way back, look at the wall across the moat. The discolored bit is a secret door. Stuff awaits.

Go past the yellow door, the big lift and around the toxic pond with the two columns. There is a secret door in the notch in the wall opposite the switch.

...Inside secret #3, tap the left hand wall for another secret...

...And inside #4, tap the back wall for yet another one!

Leaving the last secret, go to the left around the toxic pool. Half-way to the lift, you will trigger a smaller lift. Ride that up. When you touch the wall, a secret door opens, revealing shotgun ammo. The secret triggers, when you walk in to take the ammo.

The back wall is another secret door, but it doesent trigger any secret. It leads to a teleporter - and out in the open yard in front of the yellow door.

You have entered the room you could see when you did the... John Wayne thing. At the very back, there is a switch, that will open the path forward. In the wall corner to the right of the switch, there is a electronics panel. It hides a secret door, with goodies behind.

Right inside the blue door you will see... not a lot. Rather bad light. Follow the wall to the left inside the door, enter the notch... and a secret room with goodies. One in particular will be handy.

Going a bit further to the left from #8, there is a discolored wall behind a barrel. Secret door. It leads to the teleporter you already have visited. But now it counts as a secret!