Gameshark Codes
Here are gameshark codes forPerfect Dark.  For this game, don't expect to see the spectacular codes we saw for Goldeneye, because this game uses the expansion pack, but so does the Gameshark, so we can't make codes as easily!
infinite ammo & all guns unlocking  levels and other things moon jump in multi (w/o expansion pack)

Enable code:  If you have a gameshark version 3.2 or 3.3, you can put this code on, just turn the code generator on.
EE000000 0000

Low Resolution multi player codes- you still need codes for each player, but the codes work for all levels!  So it's definetly worth it.

First Player codes:
All guns:
D013EE6F 001E
8013EE70 0007

Infinite Ammo (Right Gun)
D013EE6F 001E
8013DE5B 00FF

Infinite Ammo (Left Gun)
D013EE6F 001E
8013E5FF 00FF

Second Player Codes:
All guns:
D0140ADF 001E
80140AE0   0007

Infinite Ammo (Right Gun)
D0140ADF 001E
8013FACB 00FF

Infinite Ammo (Left Gun)
D0140ADF 001E
8014026F 00FF

Unlock level codes-  Use them in low resolution, then beat a challenge to save the game, then load your game in high resolution, and the new arena will still be there for you to use.

All levels unlocked (need gs 3.0+)-
50000E01 0000
800ACCEB 0001

Unlock individual levels:
Car Park:  800ACCEB 0001
Complex:  800ACCEC 0001
Warehouse:  800ACCED 0001
Ravine:  800ACCEE 0001
Temple:  800ACCEF 0001
G5 Building:  800ACCF0 0001
Grid:  800ACCF1 0001
Felicity:  800ACCF2 0001
Villa:  800ACCF3 0001
Sewers:  800ACCF4 0001
Ruins:  800ACCF5 0001
Base:  800ACCF6 0001
Fortress:  800ACCF8 0001

Have all gold medals at the firing range-  these can be entered with the expansion pack out, then save the game, run it with the expansion pack in,a nd you have all golds!  GrayVader made this awesome code!
810A22B0 FFFF
810A22B2 FFFF

High Resolution Codes

Must Be on Codes- to use any codes, you must use the code for your version GameShark

If you are lucky enough to have a Gameshark version 3.3, enter thisone line code:
FF1EAE00 0000

If you have a 3.0 or 3.2, enter this god-forsaken 50 line code:
F1000204 27BD 
F1000206 FFE4 
F1000208 AFA8 
F100020A 0014 
F100020C AFA9 
F100020E 0018 
F1000210 3C1A 
F1000212 A05F 
F1000214 375A 
F1000216 AE00 
F1000218 3C08 
F100021A A07C 
F100021C 3508 
F100021E 5C00 
F1000220 241B 
F1000222 0040 
F1000224 8D09 
F1000226 0000 
F1000228 237B 
F100022A FFFF 
F100022C AF49 
F100022E 0000 
F1000230 2108 
F1000232 0004
F1000234 1F60 
F1000236 FFFB 
F1000238 235A 
F100023A 0004 
F100023C 8FA9 
F100023E 0018 
F1000240 8FA8 
F1000242 0014 
F1000244 27BD 
F1000246 001C 
F1000248 3C1A 
F100024A A05F 
F100024C 375A 
F100024E AE00 
F1000250 0340 
F1000252 0008 
F1000254 2400 
81000204 3C1A 
81000206 A05F 
81000208 375A 
8100020A AE00 
8100020C 0340 
8100020E 0008 
81000210 2400
Once you have the enable code entered, you can use the following codes.  Keep in mind they work for all levels.

Partial Invincibility.  As long as you are looking at an enemy, they won't shoot you.  But they can still punch/hit you.
8025FE88 0001

No blood on enemies.
80246988 0001

Walk through most locked doors.  Fun to use on Agent, to explore the rest of the level.
8022E5FC 0001

If that doesn't let you walk thru the door you want, use this code:
8022E608 0001

Or this one, but DO NOT use them all at the same time.
8022E5F8 0001
Moon Jump codes!  When you are running off of something, like a wall, or running down stairs or a ramp, hold down the B button to fly in the air!  All of these codes are by Crocc.
D009C7E4 0040 
8113D680 40F2 
D009C7E4 0040 
8013D633 0000 

D009C7EC 0040 
8113F2F0 40F2 
D009C7EC 0040 
8013F2A3 0000

(The above codes do not work on the fortress level) 

D009C7E4 0040 
8113AE80 40F2 
D009C7E4 0040 
8013AE33 0000 

D009C7EC 0040 
8113CAF0 40F2 
D009C7EC 0040 
8013CAA3 0000