Brute Force Cheats

Mission 6 (Lonesome Death of Edward Kingman):
At the very end of chaper 1, just before jumping off the cliff, the hat will be located at the begining of the wall on the right side inside a small concrete shed. It's right behind the last zombie you'll kill before the second part of the mission begins.

Mission 7 (Ship Graveyard):
You can find the hat in the middle of this level. Just before a couple of Ferals jump out of the water from hiding, there are 2 or 3 guard towers. The hat is located in the highest guard tower.

Mission 4 (Hunting for Shadoon):
A hat will appear in the first weapons depot right after you rescue the spy. It'll be in the middle of that room.

Mission 5 (Terrorist Ghetto):
In the underground area beside the pyramid structure, there will be a computer terminal that only Hawk can access. Right beside that terminal is a toxic waste bucket. Blow up the toxic waste and the hat will appear.

Note: You'll need to finish the final mission on Brutal difficulty in order to access any hats. Getting 100% on a mission is not required.

Mission 1: At the beginning of the level, there should be two sets of oil drums directly in front of you. Destroy the barrels on the left and Tex's Hat should appear.

Mission 4: After crossing the pipe over the toxic slime at the beginning of the level, there will be three sheds below you. One of the sheds has a tire on the roof. If you've beaten The Anvil on Brutal, Tex's Hat will appear on this roof.

Mission 9 (Seers on the Bayou)
The hat is located on the top of the first guard gates (early on in the first chapter).

Mission 11 (Supermutant)
The hat is on roof of a shed. Walk up on a large pipe and jump onto the roof. This is at the very begining of the mission before going through first set of gates.

Mission 18 (The Anvil):

Right at the beginning of Chapter 2, look to your right and you should see some Medkits and ammo behind a structure. If you've beaten this level on Brutal, the Hat will also be there.

Mission 15 (Hostile Reception)
Immediately after rescuing the marines (about halfway through the mission), go to the top of the hill where there will be a cave filled with supplies. The hat is located with those supplies.

Mission 12 (Kill Shadoon)
The hat is located in a weapons depot on the last chapter of Mission 12 (where you have to destroy those 8 yellow markers on the ceiling right before facing Shadoon).

Mission 10 (Squirm):

When the level begins, look out to the lowground below and you should see two giant pipes climbing a hill to your left. If you take the path inbetween these paths it leads to a good sniper spot, but that's not where the hat is. Jump unto the pipe on the right side of the path and walk up it. The hat will be there, but careful, there's also a sentry mine!

The hat on mission 3 is located on the roof of one of those huts after you have crossed the pipe over the sludge pool.

The hat on mission 17 is located on top of the temple near the dna canister.

Mission 14 . Head through the second of the gateways and enter the second building on your left. There is a humvee parked inside and a ramp that leads to the basement. The hat lies at the bottom of the ramp.

Mission 16. As you start the mission head along the left hand side. Soon you will come to an alcove which is blocked at the end by big rocks. Behind the smaller rock lies the hat

The hat in level 8 return to osiris lies in one of the huts in chaper 2. The hut is near where one of the energy pipes crosses your path. Follow this pipe from where it is severed(you cross through the gap anyway) where it leads up to the hut which contains the hat.