Crysis

Cheat Codes:
------------ 
Head to the difficulty files in your Crysis folder (for example: 
C:\Program Files\Electronic Arts\Crytek\Crysis\Game\Config). 
The four files you're looking for are titled diff_easy.cfg, 
diff_normal.cfg, diff_hard.cfg and diff_bauer.cfg. Open the file 
(using Notepad) of the difficulty level you are currently playing 
or wish to edit. 

Add the following line to the end of the file and save it:

God Mode        - g_godMode = 1 
No Target       - ai_IgnorePlayer = 1 
No Weapon Limit - i_noweaponlimit = 1 
Unlimited Ammo  - i_unlimitedammo = 1

You can also modify your suit stats. For example:
g_playerHealthValue = 400.0 
g_playerSuitArmorModeHealthRegenTime = 0 
g_playerSuitArmorModeHealthRegenTimeMoving = 0 
g_playerSuitEnergyRechargeDelay = 0 
g_playerSuitEnergyRechargeTimeArmor = 0 
g_playerSuitEnergyRechargeTimeArmorMoving = 0 
g_playerSuitEnergyRechargeTime = 0 
g_playerSuitHealthRegenDelay = 0 
g_playerSuitHealthRegenTime = 0 
g_playerSuitHealthRegenTimeMoving = 0 
g_suitArmorHealthValue = 400.0 
g_suitCloakEnergyDrainAdjuster = 0 
g_suitRecoilEnergyCost = 0 
g_suitSpeedEnergyConsumption = 0 
g_suitSpeedMult = 2

After making all of your edits, save the file, load up a new game 
and see what you've edited!


God Mode:
---------
Submitted by: RM

Locate  the  difficulty  files in your Crysis installation folder
(ie: C:\Program Files\Electronic Arts\Crytek\Crysis\Game\Config).
These files  are called diff_easy.cfg, diff_normal.cfg, diff_hard.cfg
and diff_bauer.cfg. Open the file (with Notepad) that corresponds to
the difficulty level you are playing. Add the following line to the
end of the file and save it:

g_godMode = 1 

Now, when playing  your health will still decrease but you will
not die. Instead, your health and armor will automatically replenish
when your health reaches 0.

Unlimited Ammo:
---------------
Using the same method as above, add the following line to the end
of your config file:

i_unlimitedammo = 1 

Your ammo will be frozen in the game. 

NOTE: ALWAYS MAKE A BACKUP BEFORE OVERWRITING GAME FILES.