Note: This procedure requires editing a game file; creating a backup copy of the file before proceeding. Using a text editor, 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, activate the following cheats by entering the corresponding codes:

CHEAT FUNCTION - CHEAT CODE
Invincibility - X
Kill all visible enemies - BACKSPACE
Full health - INSERT
Secondary weapon ammo - PAGE UP
Main weapon ammo - HOME