All Weapons, Infinite Ammo, and Infinite Health Packs
Face north. In the inventory highlight small health pack. Press and hold L1,L2,R1,R2, and UP.
Gold Skulls in the Training Level
The first skull is at the beginning toward the left. The second skull found is in the shallow water below the very first jump you are instructed to do. The third is below the running jump section of training. The fourth one found is in the water of your swim training session. The fifth one is found during the outdoor sequence where the old man is fighting two of the wild boars. It's around to the right, all the way into a right hand corner. The sixth one is on the floor on the right side of the room where the spikes are near the exit door just before Lara goes out to learn to crawl through the crawlspace. The seventh one is the one in the crawlspace The eighth one is on an elevated ledge/walkway that's off to the right where Lara follows the old man up the ramp just before he makes the speech about going left or right depending.
Have Lara face exaclty north. Then enter the inventory and look at the compass if the red point is not blinking slightly reposition Lara again. Go to load hold L1+L2+R2+R1+UP, then press triangle right as the compass hands point direclty north. Close the inventory to advance to the next level.
Have Lara face north, and enter the inventory screen. Go to the large medipak, and hold L1+L2+R1+R2+Down, then press Triangle right as the compass hand points north. Close the inventory screen and reopen it. All weapons should now show "Unlimited Ammo".