To get the following codes to work, Lara must be facing abolute North. One way to do this is to find a block or ledge that's facing north and climb it. You can confirm this by checking your compass - the red side should be pointing North.
Now enter the following codes:
Face North. Go to to the Inventory screen. Go to "load." Now hold L1, L2, R1, R2, Up, and press Triangle. Exit the Inventory screen to skip the level.
Face North. Go to the Inventory screen and select "small medipak." Now hold L1, L2, R1, R2, Up, and press Triangle. Exit the Inventory screen and reopen it to have every weapon.
All items on the level:
Face North. Go to the Inventory screen and select "large medipak." Now hold L1, L2, R1, R2, Down, and press Triangle. Exit the Inventory screen and reopen it. You should now have infinite amounts of every item.
All Secrets Found 800b34160046 Infinite Air 800ac30e06b2 Have Pistols 300ac41400ff Have Uzi 300ac41500ff Have Shotgun 300ac41600ff Have Crossbow 300ac41700ff
& LaserSight Have Grenade Gun 300ac41800ff Have Revolver 300ac41900ff
& LaserSight Have LaserSight 300ac41a0001 Unlimited Small 800ac43cffff
Medipacks Unlimited Large 800ac43effff
Medipacks Unlimited Flares 800ac440ffff Unlimited Uzi Ammo 800ac444ffff Unlimited Revolver Ammo 800ac446ffff Unlimited Normal 800ac448ffff
Shotgun Ammo Unlimited Wideshot 800ac44affff
Shotgun Ammo Unlimited Normal 800ac44cffff
Grenade Ammo Unlimited Super 800ac44effff
Grenade Ammo Unlimited Flash 800ac450ffff
Grenade Ammo Unlimited Normal 800ac452ffff
Crossbow Ammo Unlimited Poison 800ac454ffff
Crossbow Ammo Unlimited Explosive 800ac456ffff
Crossbow Ammo Spider Lara 800ac3060001
(Lara can climb almost any wall)
Thanks to Revolution readers G-Dogg, Jarred, Muhammad Haziq Hj Mohammad Jamil, ben, Fido, Steve Seath, and Frydaddy!