To enter these cheats just pause the game and press ESC then enter one of the
following codes. 

Use These in All Modes 

painless    Invincibility 
fogging     Toggle Fogging on/off 
followme    Camera Control 

Use These in Driving Mode 

ghost       Drive Anywhere 
nitro       Infinite Nitro 
freeze      Toggle Time Limit 
chantastic  Fast Driving 
snow        Get Snow 
susonly     Drive Only With Tires 

Use these in Sharpshooting Mode 

weapons     Get All Weapons 
ammo        Infinite Ammo 
autoreload  Toggle Autoreload on/off 
autofire    Toggle Autofire on/off 
slowmo      Slo Motion Mode 
slowrocket  Slow Rockets 

Use These in Action/Adventure Mode 

weapons       Get All Weapons 
ammo          Infinite Ammo 
freeze        Freeze Enemies 
targeting     Toggle Auto Targeting 
laser         Toggle Laser Targeting 
ghost         Go Anywhere 
followterrain-High Jumping 
mrbones       Be a Skeleton 
shocked       Be Electric 
fps-1st       Person Views 
fragyuck      More Blood 
pillowmode    Small Heads 
bighead       Big Heads