Expert mode
 
 Successfully complete the game after finding all fifteen dog tags and save.
 Start another game with the yellow "Rear Of Compound" save file (00:00:00
 time). The game will begin with extra ammunition (500 bullets, 50 shotgun
 shells, 30 grenade rounds, 1,000 flame units, and 25 Ultimate Launcher
 missiles) and extra health items (20 Recovery Unit A, 5 Recovery Unit B, 5 MTS
 Vaccine, 5 Booster Shot A and 3 Booster Shot B). However, enemies will be more
 difficult in this mode. -From: Olikong@aol.com
 
 Secret mode
 
 Successfully complete the game after finding all fifteen dog tags and Roger's
 knife. After the credits, and the funny candy girl song, you can save the game.
 When you do save the game, the save file will be yellow and have a star next to
 it. When you load this saved game file, you will begin with 300 bullets, 50
 shotgun shells, 99 grenade shells, 1000 flame thrower capacity, and 25
 missiles. You will also start out with an AT-6 Grenade Launcher. This has a six
 chamber revolving unit that you can use. You also get 25 recovery unit type A,
 5 type B, 5 MTS vaccines, 5 booster shot type A, and 3 booster shot type B.
 However, the enemies take double the hits to kill in this mode. -From:
 Olikong@aol.com
 
 Dog tag locations
 
 The following are the locations of the dog tags in order of when you find them:
 
 #5 Corporal Ross Dixon. Once the dust clears from the train wreck in the train
 area, go through the hole the train made. On the platform to the right, between
 two metal boxes, is the dog tag.
 
 #4 Corporal Arthur McDonnel. In the Command Center (where you use the 51204791
 code in the computer) reach the side where the computer is located. If in the
 box, the dog tag is to the left of the computer, outside. Go to the outside
 corner of the box, where you can look over the electric stream. The dog tag is
 next to the box. You should see it shining.
 
 #1 Private First Class Hans Grant. After defeating the Boss from the freight
 elevator, the dog tag is left behind, on the treadmill.
 
 #12 Lieutenant Mat Shuggart. After grabbing the parka, go up the ladder next to
 where you came out. Up there you should see the dog tag before the bridge
 across to the corpse and the detonator.
 
 #11 Second Lieutenant Chris Ditter. After coming in the Filtration Plant
 through the tool shed (you came in a by a ladder), make your way to the left.
 There should be a slope with a little bit of ledge. Climb across that ledge and
 make it to the platform across. Get up on the little bit higher platform. Under
 the platform, is the dog tag.
 
 #9 Officer Cadet Ed Collate. After getting the dog tag receiver unit, duck
 under the platform next to the staircase. Slice the trip wire, then collect the
 goodies: A SPR4 magazine, shotgun shells, a flame thrower tank, and dog tag #9.
 
 #6 Sergeant Robert Cameron. Near the wrecked train, where you first meet the
 watchdogs, use the dog tag receiver unit to find it.
 
 #7 Sergeant David Murren. Once coming through the door of the train room, you
 should see a booth or something straight ahead. Slice the wooden crates to the
 left of it and you should see it to the right of the steel crates.
 
 #13 Captain Kurt Gianini. Up the stairs, in the same room, there should be a
 vent in the area where you look down on the booth area. Once in, take the first
 right and go straight until you reach the end. Turn right and there they should
 be at the end.
 
 #3 Private First Class Tom Taylor. In the room with the metal tag, same area as
 the other two above. You should find it by the metal tag.
 
 #10 Officer Cadet Lance McLaughlin. After confronting Cindy, you should find
 this tag in the corner near her.
 
 #2 Corporal Filel Sidalis. On the ledge outside, near Filel, there is the dog
 tag on the ledge. Use the dog tag receiver unit.
 
 #14 Sergeant Roger Grigman. After defeating Roger, the dog tag should be just
 before the bridge. Also take his knife.
 
 #15 Major Mike Madigan. After defeating Roger, go to where the wounded Madigan
 is located. Once the FMV sequence is over, his dog tags will be next to the
 elevator-like thing where he descended into the Facility.
 
 #8 First Sergeant Ken Reschner. In the area with the ice camo car, the dog tag
 is in the corner of a little outcropping. You should now have 14 out of 15 dog
 tags.
 
 Game Shark Codez:
 
              
 Master Code (Must Be On)   
 EC8D3170 1445DC6C
              
 Infinite Health            
 4C188B7E 145625DD
 4C1887F6 145625DD
              
 0% Infection               
 4C1887FE 1456E7A5
 4C188B82 1456E7A5
              
 Infinite/Max Battery       
 3C188FD6 1456E7D5
 3C188FDB 1456E7D5
              
 Infinite MTS Vaccine       
 3C188FAC 1456E788
              
 Infinite Recovery Unit A   
 3C188FA6 1456E788
              
 Infinite Recovery Unit B   
 3C188FA7 1456E788
              
 Infinite Booster Type A    
 3C188FAD 1456E788
              
 Infinite Booster Type B    
 3C188FAA 1456E788
              
 Infinite Shotgun Shells    
 4C188FD0 1456089C
              
 Infinite Machinegun Ammo   
 4C188FDC 1456089C
              
 No Reloads Machinegun      
 3C188F86 1456E70C
              
 Infinite Grenade Rounds    
 4C188FCE 1456089C
              
 Infinite Flamethrower Fuel 
 1C188FD4 1473E788
              
 No Reload Flamethrower     
 4C188FD2 1456E788
              
 Infinite Rockets           
 4C188FD8 1456089C
              
 Have Climbing Spikes       
 3C188FA5 1456E7A6
              
 Have Arctic Parka          
 3C188FA2 1456E7A6
              
 Low Time                   
 1C188878 1456E7A5
              
 All Weapon Parts           
 1C188F8C 1355E6A6
 1C188F90 1355E6A6
 1C188F94 1355E6A6
 1C188F98 1355E6A6
              
 Have All Top Secret Files  
 1C188E48 1355E6A6
 1C188E4C 1355E6A6
 1C188E50 1355E6A6
 1C188E54 1355E6A6
              
 Have All Operation Manuals 
 3C188F07 1456E7A6
 1C188F0C 1355E6A6
 1C188F10 1355E6A6
 1C188F14 1355E6A6
 1C188F18 1355E6A6
 3C188F1C 1456E7A6
              
 Have All Classified Files  
 3C188E2F 1456E7A6
 1C188E34 1355E6A6
 1C188E38 1355E6A6
 1C188E3C 1355E6A6
 1C188E40 1355E6A6
 1C188E44 1355E6A6
              
 Have All Staff Logs        
 3C188F1D 1456E7A6
 4C188F1A 1456E6A6
 1C188F20 1355E6A6
 1C188F24 1355E6A6
 1C188E28 1355E6A6
 1C188E2C 1355E6A6
 4C188E30 1456E6A6
 3C188E2E 1456E7A6
              
 Have All Dennis' Memos     
 3C188FE7 1456E7A6
 1C188FEC 1355E6A6
 1C188FF0 1355E6A6
 1C188FF4 1355E6A6
 1C188FF8 1355E6A6
 1C188FFC 1355E6A6
 1C188F00 1355E6A6
 1C188F04 1355E6A6
 4C188F08 1456E6A6
 3C188F06 1456E7A6
              
 
 Other Gameshark codez:
 
 Invincible Mode = 4C18B158 1456E6A8 
 Have Full Auto = 3C18B817 1456E7A6 
 Have Ultimate Launcher C = 3C18B816 1456E7A6 
 Have Ultimate Launcher B = 3C18B819 1456E7A6