Cheat Codes
Make a backup of "data\cfg\config.cfg" game file, and then open it using Notepad. Change any of the lines as shown below to enable cheat effects (you need to change the last character from 0 to 1 to enable an effect), and then start the game:

set ai_disable 1 - Prevents the enemies from moving or attacking
set cg_drawFps 1 - Graphical Frames Per Second displayed on-screen
set cg_drawTarget 1 - Show information about an enemy or object that is in your target
set cg_drawWeaponStats 1 - Display statistics about your weapon
set developerMenu 1 - Enable the Developer Menu items in Options
set god 1 - Enable God mode
set physics_disable 1 - Disable the laws of physics
set r_debugVis 1 - Show Debug Information about meshes and such
set r_debugVisBox 2 - Show debug boxes (like wireframe) on objects
set showNavForPlayer 1 - Unknown
set wheelSpeeder 1 - Unknown