Tomb Raider 4: The Last Revelation

Level skip:
Have Lara face exactly north.
Enter the inventory screen and look at the compass.
If it is not blinking, try positioning her again.
Go to "Load", hold L1 + L2 + R1 + R2 + Up, then press Triangle.
Close the inventory screen to advance to the next level.

All weapons:
Have Lara face exactly north.
Go to the large medipak, hold L1 +L2 + R1 + R2 + Up, then press Triangle.

Unlimited items:
Have Lara face exactly north.
Go to the small medipak, hold L1 +L2 + R1 + R2 + Down, then press Triangle.
(Information from Cheat Machine)