Note: This procedure involves editing a game file; create a 
backup copy of the file before proceeding. Use a text editor 
to edit the "hardline.cfg" file. Add the case-sensitive entry
"CHEATING IS SOMETIMES USEFUL BUT FOR HOW LONG ???" at the 
end of the file to enable cheat mode. 
Then, press one of the following keys during game play.

Effect                    Key
----------------------------- 
Invincibility             [X] 
Kill all visible enemies  [Backspace] 
Full health               [Insert] 
Secondary weapon ammo     [Page Up] 
Main weapon ammo          [Home]